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Gold is a
chemical element A chemical element is a chemical substance whose atoms all have the same number of protons. The number of protons is called the atomic number of that element. For example, oxygen has an atomic number of 8: each oxygen atom has 8 protons in its ...
; it has
chemical symbol Chemical symbols are the abbreviations used in chemistry, mainly for chemical elements; but also for functional groups, chemical compounds, and other entities. Element symbols for chemical elements, also known as atomic symbols, normally consist ...
Au (from
Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
) and
atomic number The atomic number or nuclear charge number (symbol ''Z'') of a chemical element is the charge number of its atomic nucleus. For ordinary nuclei composed of protons and neutrons, this is equal to the proton number (''n''p) or the number of pro ...
79. In its pure form, it is a bright, slightly orange-yellow, dense, soft,
malleable Ductility refers to the ability of a material to sustain significant plastic deformation before fracture. Plastic deformation is the permanent distortion of a material under applied stress, as opposed to elastic deformation, which is reversi ...
, and
ductile Ductility refers to the ability of a material to sustain significant plastic deformation before fracture. Plastic deformation is the permanent distortion of a material under applied stress, as opposed to elastic deformation, which is reversi ...
metal A metal () is a material that, when polished or fractured, shows a lustrous appearance, and conducts electrical resistivity and conductivity, electricity and thermal conductivity, heat relatively well. These properties are all associated wit ...
. Chemically, gold is a
transition metal In chemistry, a transition metal (or transition element) is a chemical element in the d-block of the periodic table (groups 3 to 12), though the elements of group 12 (and less often group 3) are sometimes excluded. The lanthanide and actinid ...
, a
group 11 element Group 11, by modern IUPAC numbering, is a group (periodic table), group of chemical elements in the periodic table, consisting of copper (Cu), silver (Ag), gold (Au), and roentgenium (Rg), although no chemical experiments have yet been carried ...
, and one of the
noble metal A noble metal is ordinarily regarded as a metallic chemical element, element that is generally resistant to corrosion and is usually found in nature in its native element, raw form. Gold, platinum, and the other platinum group metals (ruthenium ...
s. It is one of the least reactive chemical elements, being the second-lowest in the
reactivity series In chemistry, a reactivity series (or reactivity series of elements) is an empirical, calculated, and structurally analytical progression of a series of metals, arranged by their "reactivity" from highest to lowest. It is used to summarize inform ...
. It is solid under standard conditions. Gold often occurs in
free element In chemistry, a free element is a chemical element that is not combined with or chemically bonded to other elements. Examples of elements which can occur as free elements include the molecular oxygen (O) and carbon as diamond or graphite.A. Earn ...
al (
native state In biochemistry, the native state of a protein or nucleic acid is its properly Protein folding, folded and/or assembled form, which is operative and functional. The native state of a biomolecule may possess all four levels of biomolecular structu ...
), as nuggets or grains, in rocks,
veins Veins () are blood vessels in the circulatory system of humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are those of the pulmonary and fetal c ...
, and alluvial deposits. It occurs in a
solid solution A solid solution, a term popularly used for metals, is a homogeneous mixture of two compounds in solid state and having a single crystal structure. Many examples can be found in metallurgy, geology, and solid-state chemistry. The word "solutio ...
series with the native element
silver Silver is a chemical element; it has Symbol (chemistry), symbol Ag () and atomic number 47. A soft, whitish-gray, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. ...
(as in
electrum Electrum is a naturally occurring alloy of gold and silver, with trace amounts of copper and other metals. Its color ranges from pale to bright yellow, depending on the proportions of gold and silver. It has been produced artificially and is ...
), naturally
alloy An alloy is a mixture of chemical elements of which in most cases at least one is a metal, metallic element, although it is also sometimes used for mixtures of elements; herein only metallic alloys are described. Metallic alloys often have prop ...
ed with other metals like
copper Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...
and
palladium Palladium is a chemical element; it has symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1802 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas (formally 2 Pallas), ...
, and
mineral inclusion In mineralogy, an inclusion is any material trapped inside a mineral during its formation. In gemology, it is an object enclosed within a gemstone or reaching its surface from the interior. According to James Hutton's law of inclusions, fragment ...
s such as within
pyrite The mineral pyrite ( ), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic luster and pale brass-yellow hue ...
. Less commonly, it occurs in minerals as gold compounds, often with
tellurium Tellurium is a chemical element; it has symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally fou ...
(
gold telluride Gold chalcogenides are compounds formed between gold and one of the chalcogens, elements from group 16 of the periodic table: oxygen, sulfur, selenium, or tellurium. * Gold(III) oxide, Au2O3. Decomposes into gold and oxygen above 160 °C, and ...
s). Gold is resistant to most acids, though it does dissolve in
aqua regia Aqua regia (; from Latin, "regal water" or "royal water") is a mixture of nitric acid and hydrochloric acid, optimally in a molar concentration, molar ratio of 1:3. Aqua regia is a fuming liquid. Freshly prepared aqua regia is colorless, but i ...
(a mixture of
nitric acid Nitric acid is an inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but samples tend to acquire a yellow cast over time due to decomposition into nitrogen oxide, oxides of nitrogen. Most com ...
and
hydrochloric acid Hydrochloric acid, also known as muriatic acid or spirits of salt, is an aqueous solution of hydrogen chloride (HCl). It is a colorless solution with a distinctive pungency, pungent smell. It is classified as a acid strength, strong acid. It is ...
), forming a soluble tetrachloroaurate
anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conven ...
. Gold is insoluble in nitric acid alone, which dissolves silver and
base metal A base metal is a common and inexpensive metal, as opposed to a precious metal such as gold or silver. In numismatics, coins often derived their value from the precious metal content; however, base metals have also been used in coins in the past ...
s, a property long used to refine gold and confirm the presence of gold in metallic substances, giving rise to the term " acid test". Gold dissolves in
alkaline In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The ...
solutions of
cyanide In chemistry, cyanide () is an inorganic chemical compound that contains a functional group. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom. Ionic cyanides contain the cyanide anion . This a ...
, which are used in
mining Mining is the Resource extraction, extraction of valuable geological materials and minerals from the surface of the Earth. Mining is required to obtain most materials that cannot be grown through agriculture, agricultural processes, or feasib ...
and
electroplating Electroplating, also known as electrochemical deposition or electrodeposition, is a process for producing a metal coating on a solid substrate through the redox, reduction of cations of that metal by means of a direct current, direct electric cur ...
. Gold also dissolves in mercury, forming amalgam alloys, and as the gold acts simply as a solute, this is not a
chemical reaction A chemical reaction is a process that leads to the chemistry, chemical transformation of one set of chemical substances to another. When chemical reactions occur, the atoms are rearranged and the reaction is accompanied by an Gibbs free energy, ...
. A relatively rare element, gold is a
precious metal Precious metals are rare, naturally occurring metallic chemical elements of high Value (economics), economic value. Precious metals, particularly the noble metals, are more corrosion resistant and less reactivity (chemistry), chemically reac ...
that has been used for coinage,
jewelry Jewellery (or jewelry in American English) consists of decorative items worn for personal adornment such as brooches, ring (jewellery), rings, necklaces, earrings, pendants, bracelets, and cufflinks. Jewellery may be attached to the body or the ...
, and other works of art throughout
recorded history Recorded history or written history describes the historical events that have been recorded in a written form or other documented communication which are subsequently evaluated by historians using the historical method. For broader world h ...
. In the past, a
gold standard A gold standard is a backed currency, monetary system in which the standard economics, economic unit of account is based on a fixed quantity of gold. The gold standard was the basis for the international monetary system from the 1870s to the ...
was often implemented as a
monetary policy Monetary policy is the policy adopted by the monetary authority of a nation to affect monetary and other financial conditions to accomplish broader objectives like high employment and price stability (normally interpreted as a low and stable rat ...
. Gold coins ceased to be minted as a circulating currency in the 1930s, and the world gold standard was abandoned for a
fiat currency Fiat money is a type of government-issued currency that is not backed by a precious metal, such as gold or silver, nor by any other tangible asset or commodity. Fiat currency is typically designated by the issuing government to be legal tender, ...
system after the Nixon shock measures of 1971. In 2023, the world's largest gold producer was China, followed by Russia and Australia. , a total of around 201,296
tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1,000  kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton in the United States to distinguish it from the non-metric units of the s ...
s of gold exist above ground. If all of this gold were put together into a cube shape, each of its sides would measure . The world's consumption of new gold produced is about 50% in jewelry, 40% in
investment Investment is traditionally defined as the "commitment of resources into something expected to gain value over time". If an investment involves money, then it can be defined as a "commitment of money to receive more money later". From a broade ...
s, and 10% in
industry Industry may refer to: Economics * Industry (economics), a generally categorized branch of economic activity * Industry (manufacturing), a specific branch of economic activity, typically in factories with machinery * The wider industrial sector ...
. Gold's high malleability, ductility, resistance to corrosion and most other chemical reactions, as well as conductivity of electricity have led to its continued use in corrosion-resistant
electrical connector Components of an electrical circuit are electrically connected if an electric current can run between them through an electrical conductor. An electrical connector is an electromechanical device used to create an electrical connection between ...
s in all types of computerized devices (its chief industrial use). Gold is also used in
infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...
shielding, the production of colored glass,
gold leaf upA gold nugget of 5 mm (0.2 in) in diameter (bottom) can be expanded through hammering into a gold foil of about 0.5 m2 (5.4 sq ft). The Japan.html" ;"title="Toi gold mine museum, Japan">Toi gold mine museum, Japan. Gold leaf is gold that has ...
ing, and tooth restoration. Certain
gold salts Gold-containing drugs are pharmaceuticals that contain gold. Sometimes these species are referred to as "gold salts". "Chrysotherapy" and "aurotherapy" are the applications of gold compounds to medicine. Research on the medicinal effects of g ...
are still used as
anti-inflammatory Anti-inflammatory is the property of a substance or treatment that reduces inflammation, fever or swelling. Anti-inflammatory drugs, also called anti-inflammatories, make up about half of analgesics. These drugs reduce pain by inhibiting mechan ...
agents in medicine.


Characteristics

Gold is the most
malleable Ductility refers to the ability of a material to sustain significant plastic deformation before fracture. Plastic deformation is the permanent distortion of a material under applied stress, as opposed to elastic deformation, which is reversi ...
of all metals. It can be drawn into a wire of single-atom width, and then stretched considerably before it breaks. Such nanowires distort via the formation, reorientation, and migration of
dislocation In materials science, a dislocation or Taylor's dislocation is a linear crystallographic defect or irregularity within a crystal structure that contains an abrupt change in the arrangement of atoms. The movement of dislocations allow atoms to sli ...
s and crystal twins without noticeable hardening. A single gram of gold can be beaten into a sheet of , and an avoirdupois ounce into . Gold leaf can be beaten thin enough to become semi-transparent. The transmitted light appears greenish-blue because gold strongly reflects yellow and red. Such semi-transparent sheets also strongly reflect
infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...
light, making them useful as infrared (radiant heat) shields in the visors of heat-resistant suits and in sun visors for
spacesuit A space suit (or spacesuit) is an environmental suit used for protection from the harsh Space environment, environment of outer space, mainly from its Vacuum (outer space), vacuum as a highly specialized pressure suit, but also its temperatu ...
s. Gold is a good conductor of heat and
electricity Electricity is the set of physical phenomena associated with the presence and motion of matter possessing an electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as described by Maxwel ...
. Gold has a density of 19.3 g/cm3, almost identical to that of
tungsten Tungsten (also called wolfram) is a chemical element; it has symbol W and atomic number 74. It is a metal found naturally on Earth almost exclusively in compounds with other elements. It was identified as a distinct element in 1781 and first ...
at 19.25 g/cm3; as such, tungsten has been used in the
counterfeiting A counterfeit is a fake or unauthorized replica of a genuine product, such as money, documents, designer items, or other valuable goods. Counterfeiting generally involves creating an imitation of a genuine item that closely resembles the original ...
of
gold bar A gold bar, also known as gold bullion or a gold ingot, is a quantity of refined metallic gold that can be shaped in various forms, produced under standardized conditions of manufacture, labeling, and record-keeping. Larger varieties of gold ...
s, such as by plating a tungsten bar with gold. By comparison, the density of
lead Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...
is 11.34 g/cm3, and that of the densest element,
osmium Osmium () is a chemical element; it has Symbol (chemistry), symbol Os and atomic number 76. It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a Abundance of elements in Earth's crust, trace element in a ...
, is .


Color

Whereas most metals are gray or silvery white, gold is slightly reddish-yellow. This color is determined by the frequency of
plasma oscillation Plasma oscillations, also known as Langmuir waves (after Irving Langmuir), are rapid oscillations of the electron density in conducting media such as plasmas or metals in the ultraviolet region. The oscillations can be described as an instability ...
s among the metal's valence electrons, in the ultraviolet range for most metals but in the visible range for gold due to relativistic effects affecting the orbitals around gold atoms. Similar effects impart a golden hue to metallic
caesium Caesium (IUPAC spelling; also spelled cesium in American English) is a chemical element; it has Symbol (chemistry), symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal with a melting point of , which makes it one of only f ...
. Common colored gold alloys include the distinctive eighteen-karat rose gold created by the addition of copper. Alloys containing
palladium Palladium is a chemical element; it has symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1802 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas (formally 2 Pallas), ...
or
nickel Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slo ...
are also important in commercial jewelry as these produce white gold alloys. Fourteen-karat gold-copper alloy is nearly identical in color to certain
bronze Bronze is an alloy consisting primarily of copper, commonly with about 12–12.5% tin and often with the addition of other metals (including aluminium, manganese, nickel, or zinc) and sometimes non-metals (such as phosphorus) or metalloid ...
alloys, and both may be used to produce police and other
badge A badge is a device or accessory, often containing the insignia of an organization, which is presented or displayed to indicate some feat of service, a special accomplishment, a symbol of authority granted by taking an oath (e.g., police and fir ...
s. Fourteen- and eighteen-karat gold alloys with silver alone appear greenish-yellow and are referred to as green gold. Blue gold can be made by alloying with
iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...
, and purple gold can be made by alloying with
aluminium Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...
. Less commonly, addition of
manganese Manganese is a chemical element; it has Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It is a transition m ...
,
indium Indium is a chemical element; it has Symbol (chemistry), symbol In and atomic number 49. It is a silvery-white post-transition metal and one of the softest elements. Chemically, indium is similar to gallium and thallium, and its properties are la ...
, and other elements can produce more unusual colors of gold for various applications.
Colloidal gold Colloidal gold is a sol or colloidal suspension of nanoparticles of gold in a fluid, usually water. The colloid is coloured usually either wine red (for spherical particles less than 100  nm) or blue-purple (for larger spherical partic ...
, used by electron-microscopists, is red if the particles are small; larger particles of colloidal gold are blue.


Isotopes

Gold has only one stable
isotope Isotopes are distinct nuclear species (or ''nuclides'') of the same chemical element. They have the same atomic number (number of protons in their Atomic nucleus, nuclei) and position in the periodic table (and hence belong to the same chemica ...
, , which is also its only naturally occurring isotope, so gold is both a mononuclidic and
monoisotopic element A monoisotopic element is an element which has only a single stable isotope (nuclide). There are 26 such elements, as listed. Stability is experimentally defined for chemical elements, as there are a number of stable nuclides with atomic number ...
. Thirty-six radioisotopes have been synthesized, ranging in
atomic mass Atomic mass ( or ) is the mass of a single atom. The atomic mass mostly comes from the combined mass of the protons and neutrons in the nucleus, with minor contributions from the electrons and nuclear binding energy. The atomic mass of atoms, ...
from 169 to 205. The most stable of these is with a
half-life Half-life is a mathematical and scientific description of exponential or gradual decay. Half-life, half life or halflife may also refer to: Film * Half-Life (film), ''Half-Life'' (film), a 2008 independent film by Jennifer Phang * ''Half Life: ...
of 186.1 days. The least stable is , which decays by
proton emission Proton emission (also known as proton radioactivity) is a rare type of radioactive decay in which a proton is ejected from a atomic nucleus, nucleus. Proton emission can occur from high-lying excited states in a nucleus following a beta decay ...
with a half-life of 30 μs. Most of gold's radioisotopes with atomic masses below 197 decay by some combination of
proton emission Proton emission (also known as proton radioactivity) is a rare type of radioactive decay in which a proton is ejected from a atomic nucleus, nucleus. Proton emission can occur from high-lying excited states in a nucleus following a beta decay ...
, α decay, and β+ decay. The exceptions are , which decays by electron capture, and , which decays most often by electron capture (93%) with a minor β decay path (7%). All of gold's radioisotopes with atomic masses above 197 decay by β decay. At least 32
nuclear isomer A nuclear isomer is a metastable state of an atomic nucleus, in which one or more nucleons (protons or neutrons) occupy excited state levels (higher energy levels). "Metastable" describes nuclei whose excited states have Half-life, half-lives of ...
s have also been characterized, ranging in atomic mass from 170 to 200. Within that range, only , , , , and do not have isomers. Gold's most stable isomer is with a half-life of 2.27 days. Gold's least stable isomer is with a half-life of only 7 ns. has three decay paths: β+ decay,
isomeric transition A nuclear isomer is a metastable state of an atomic nucleus, in which one or more nucleons (protons or neutrons) occupy excited state levels (higher energy levels). "Metastable" describes nuclei whose excited states have half-lives of 10−9 s ...
, and alpha decay. No other isomer or isotope of gold has three decay paths.


Synthesis

The possible production of gold from a more common element, such as
lead Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...
, has long been a subject of human inquiry, and the ancient and medieval discipline of
alchemy Alchemy (from the Arabic word , ) is an ancient branch of natural philosophy, a philosophical and protoscientific tradition that was historically practised in China, India, the Muslim world, and Europe. In its Western form, alchemy is first ...
often focused on it; however, the transmutation of the chemical elements did not become possible until the understanding of
nuclear physics Nuclear physics is the field of physics that studies atomic nuclei and their constituents and interactions, in addition to the study of other forms of nuclear matter. Nuclear physics should not be confused with atomic physics, which studies th ...
in the 20th century. The first synthesis of gold was conducted by Japanese physicist Hantaro Nagaoka, who synthesized gold from mercury in 1924 by neutron bombardment. An American team, working without knowledge of Nagaoka's prior study, conducted the same experiment in 1941, achieving the same result and showing that the
isotopes of gold Gold (79Au) has one stable isotope, 197Au, and 40 radioisotopes, with 195Au being the most stable with a half-life of 186 days. Gold is currently considered the heaviest monoisotopic element. Bismuth formerly held that distinction until alpha-de ...
produced by it were all
radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is conside ...
. In 1980,
Glenn Seaborg Glenn Theodore Seaborg ( ; April 19, 1912February 25, 1999) was an American chemist whose involvement in the synthesis, discovery and investigation of ten transuranium elements earned him a share of the 1951 Nobel Prize in Chemistry. His work i ...
transmuted several thousand atoms of bismuth into gold at the Lawrence Berkeley Laboratory. Gold can be manufactured in a nuclear reactor, but doing so is highly impractical and would cost far more than the value of the gold that is produced.


Chemistry

Although gold is the most noble of the noble metals, it still forms many diverse compounds. The
oxidation state In chemistry, the oxidation state, or oxidation number, is the hypothetical Electrical charge, charge of an atom if all of its Chemical bond, bonds to other atoms are fully Ionic bond, ionic. It describes the degree of oxidation (loss of electrons ...
of gold in its compounds ranges from −1 to +5, but Au(I) and Au(III) dominate its chemistry. Au(I), referred to as the aurous ion, is the most common oxidation state with soft
ligand In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's el ...
s such as
thioether In organic chemistry, a sulfide (British English sulphide) or thioether is an organosulfur functional group with the connectivity as shown on right. Like many other sulfur-containing compounds, Volatile organic compound, volatile sulfides have ...
s,
thiolate In organic chemistry, a thiol (; ), or thiol derivative, is any organosulfur compound of the form , where R represents an alkyl or other organic substituent. The functional group itself is referred to as either a thiol group or a sulfhydryl grou ...
s, and
organophosphine Organophosphines are organophosphorus compounds with the formula PR''n''H3−''n'', where R is an organic substituent. These compounds can be classified according to the value of ''n'': primary phosphines (''n'' = 1), secondary phosphin ...
s. Au(I) compounds are typically linear. A good example is , which is the soluble form of gold encountered in mining. The binary gold halides, such as AuCl, form zigzag polymeric chains, again featuring linear coordination at Au. Most drugs based on gold are Au(I) derivatives. Au(III) (referred to as auric) is a common oxidation state, and is illustrated by
gold(III) chloride Gold(III) chloride, traditionally called auric chloride, is an inorganic compound of gold and chlorine with the molecular formula . The "III" in the name indicates that the gold has an oxidation state of +3, typical for many gold compounds. It ...
, . The gold atom centers in Au(III) complexes, like other d8 compounds, are typically
square planar In chemistry, the square planar molecular geometry describes the stereochemistry (spatial arrangement of atoms) that is adopted by certain chemical compounds. As the name suggests, molecules of this geometry have their atoms positioned at the co ...
, with
chemical bond A chemical bond is the association of atoms or ions to form molecules, crystals, and other structures. The bond may result from the electrostatic force between oppositely charged ions as in ionic bonds or through the sharing of electrons a ...
s that have both
covalent A covalent bond is a chemical bond that involves the sharing of electrons to form electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs. The stable balance of attractive and repulsive forces between atom ...
and
ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...
ic character.
Gold(I,III) chloride Gold(I,III) chloride is the inorganic compound with the chemical formula Au4 Cl8. It is a mixed valence compound as it contains gold in two oxidation states; square-planar gold(III) and almost linear gold(I). The compound, which is black, is pho ...
is also known, an example of a
mixed-valence complex Mixed valence complexes contain an element which is present in more than one oxidation state. Well-known mixed valence compounds include the Creutz–Taube complex, Prussian blue, and molybdenum blue. Many solids are mixed-valency including ...
. Gold does not react with oxygen at any temperature and, up to 100 °C, is resistant to attack from ozone: \ce(\text) \ce(\text) Some free
halogen The halogens () are a group in the periodic table consisting of six chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and the radioactive elements astatine (At) and tennessine (Ts), though some authors would ...
s react to form the corresponding gold halides. Gold is strongly attacked by fluorine at dull-red heat to form
gold(III) fluoride Gold(III) fluoride is an inorganic compound of gold and flourine with the molecular formula . It is an orange solid that sublimes at 300 °C. It is a powerful fluorinating agent. It is very sensitive to moisture, yielding gold(III) hydroxi ...
. Powdered gold reacts with chlorine at 180 °C to form
gold(III) chloride Gold(III) chloride, traditionally called auric chloride, is an inorganic compound of gold and chlorine with the molecular formula . The "III" in the name indicates that the gold has an oxidation state of +3, typical for many gold compounds. It ...
. Gold reacts with bromine at 140 °C to form a combination of gold(III) bromide and gold(I) bromide AuBr, but reacts very slowly with iodine to form
gold(I) iodide Gold monoiodide is the inorganic compound of gold and iodine with the formula AuI. It can be synthesized by dissolving gold powder in an aqueous solution of iodine and potassium iodide. With Lewis bases, AuI reacts to give numerous complexes. P ...
AuI: 2 Au + 3 F2 -> atop\Delta2 AuF3 2 Au + 3 Cl2 -> atop\Delta2 AuCl3 2 Au + 2 Br2 -> atop\DeltaAuBr3 + AuBr 2 Au + I2 -> atop\Delta2 AuI Gold does not react with sulfur directly, but
gold(III) sulfide Gold(III) sulfide or auric sulfide is an inorganic compound with the formula . Auric sulfide has been described as a black and amorphous solid. Only the amorphous phase has been produced, and the only evidence of existence is based on thermal anal ...
can be made by passing
hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is toxic, corrosive, and flammable. Trace amounts in ambient atmosphere have a characteristic foul odor of rotten eggs. Swedish chemist ...
through a dilute solution of gold(III) chloride or chlorauric acid. Unlike sulfur, phosphorus reacts directly with gold at elevated temperatures to produce gold phosphide (Au2P3). Gold readily dissolves in mercury at room temperature to form an amalgam, and forms
alloy An alloy is a mixture of chemical elements of which in most cases at least one is a metal, metallic element, although it is also sometimes used for mixtures of elements; herein only metallic alloys are described. Metallic alloys often have prop ...
s with many other metals at higher temperatures. These alloys can be produced to modify the hardness and other metallurgical properties, to control
melting point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state of matter, state from solid to liquid. At the melting point the solid and liquid phase (matter), phase exist in Thermodynamic equilib ...
or to create exotic colors. Gold is unaffected by most acids. It does not react with hydrofluoric, hydrochloric, hydrobromic, hydriodic,
sulfuric Sulfur (American spelling and the preferred IUPAC name) or sulphur ( Commonwealth spelling) is a chemical element; it has symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form ...
, or
nitric acid Nitric acid is an inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but samples tend to acquire a yellow cast over time due to decomposition into nitrogen oxide, oxides of nitrogen. Most com ...
. It does react with selenic acid, and is dissolved by
aqua regia Aqua regia (; from Latin, "regal water" or "royal water") is a mixture of nitric acid and hydrochloric acid, optimally in a molar concentration, molar ratio of 1:3. Aqua regia is a fuming liquid. Freshly prepared aqua regia is colorless, but i ...
, a 1:3 mixture of
nitric acid Nitric acid is an inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but samples tend to acquire a yellow cast over time due to decomposition into nitrogen oxide, oxides of nitrogen. Most com ...
and
hydrochloric acid Hydrochloric acid, also known as muriatic acid or spirits of salt, is an aqueous solution of hydrogen chloride (HCl). It is a colorless solution with a distinctive pungency, pungent smell. It is classified as a acid strength, strong acid. It is ...
. Nitric acid oxidizes the metal to +3 ions, but only in minute amounts, typically undetectable in the pure acid because of the chemical equilibrium of the reaction. However, the ions are removed from the equilibrium by hydrochloric acid, forming ions, or
chloroauric acid Chloroauric acid is an inorganic compound with the chemical formula . It forms hydrates . Both the trihydrate and tetrahydrate are known. Both are orange-yellow solids consisting of the planar anion. Often chloroauric acid is handled as a solutio ...
, thereby enabling further oxidation: 2 Au + 6 H2SeO4 -> atopAu2(SeO4)3 + 3 H2SeO3 + 3 H2O Au + 4HCl + HNO3 -> HAuCl4 + NO\uparrow + 2H2O Gold is similarly unaffected by most bases. It does not react with
aqueous An aqueous solution is a solution in which the solvent is water. It is mostly shown in chemical equations by appending (aq) to the relevant chemical formula. For example, a solution of table salt, also known as sodium chloride (NaCl), in wat ...
,
solid Solid is a state of matter where molecules are closely packed and can not slide past each other. Solids resist compression, expansion, or external forces that would alter its shape, with the degree to which they are resisted dependent upon the ...
, or molten
sodium Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...
or
potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which utili ...
. It does however, react with
sodium Sodium is a chemical element; it has Symbol (chemistry), symbol Na (from Neo-Latin ) and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 element, group 1 of the peri ...
or
potassium cyanide Potassium cyanide is a compound with the formula KCN. It is a colorless salt, similar in appearance to sugar, that is highly soluble in water. Most KCN is used in gold mining, organic synthesis, and electroplating. Smaller applications include ...
under alkaline conditions when
oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...
is present to form soluble complexes. Common
oxidation state In chemistry, the oxidation state, or oxidation number, is the hypothetical Electrical charge, charge of an atom if all of its Chemical bond, bonds to other atoms are fully Ionic bond, ionic. It describes the degree of oxidation (loss of electrons ...
s of gold include +1 (gold(I) or aurous compounds) and +3 (gold(III) or auric compounds). Gold ions in solution are readily reduced and precipitated as metal by adding any other metal as the
reducing agent In chemistry, a reducing agent (also known as a reductant, reducer, or electron donor) is a chemical species that "donates" an electron to an (called the , , , or ). Examples of substances that are common reducing agents include hydrogen, carbon ...
. The added metal is
oxidized Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...
and dissolves, allowing the gold to be displaced from solution and be recovered as a solid precipitate.


Rare oxidation states

Less common oxidation states of gold include −1, +2, and +5. The −1 oxidation state occurs in aurides, compounds containing the
anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conven ...
. Caesium auride (CsAu), for example, crystallizes in the
caesium chloride Caesium chloride or cesium chloride is the inorganic compound with the formula Caesium, CsChloride, Cl. This colorless salt is an important source of caesium ions in a variety of niche applications. Its crystal structure forms a major structural ...
motif; rubidium, potassium, and tetramethylammonium aurides are also known. Gold has the highest
electron affinity The electron affinity (''E''ea) of an atom or molecule is defined as the amount of energy released when an electron attaches to a neutral atom or molecule in the gaseous state to form an anion. ::X(g) + e− → X−(g) + energy This differs by si ...
of any metal, at 222.8 kJ/mol, making a stable species, analogous to the
halide In chemistry, a halide (rarely halogenide) is a binary chemical compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative (or more electropositive) than the halogen, to make a fl ...
s. Gold also has a –1 oxidation state in covalent complexes with the
group 4 Group 4 may refer to: *Group 4 element Group 4 is the second group of transition metals in the periodic table. It contains only the four elements titanium (Ti), zirconium (Zr), hafnium (Hf), and rutherfordium (Rf). The group is also called the t ...
transition metals, such as in titanium tetraauride and the analogous zirconium and hafnium compounds. These chemicals are expected to form gold-bridged dimers in a manner similar to titanium(IV) hydride. Gold(II) compounds are usually
diamagnetic Diamagnetism is the property of materials that are repelled by a magnetic field; an applied magnetic field creates an induced magnetic field in them in the opposite direction, causing a repulsive force. In contrast, paramagnetic and ferromagn ...
with Au–Au bonds such as The evaporation of a solution of in concentrated produces red crystals of gold(II) sulfate, . Originally thought to be a mixed-valence compound, it has been shown to contain cations, analogous to the better-known mercury(I) ion, . A gold(II) complex, the tetraxenonogold(II) cation, which contains xenon as a ligand, occurs in . In September 2023, a novel type of Perovskite (structure), metal-halide perovskite material consisting of Au3+ and Au2+ cations in its crystal structure has been found. It has been shown to be unexpectedly stable at normal conditions. Gold pentafluoride, along with its derivative anion, , and its difluorine complex, gold heptafluoride, is the sole example of gold(V), the highest verified oxidation state. Some gold compounds exhibit '' aurophilic bonding'', which describes the tendency of gold ions to interact at distances that are too long to be a conventional Au–Au bond but shorter than van der Waals bonding. The interaction is estimated to be comparable in strength to that of a
hydrogen bond In chemistry, a hydrogen bond (H-bond) is a specific type of molecular interaction that exhibits partial covalent character and cannot be described as a purely electrostatic force. It occurs when a hydrogen (H) atom, Covalent bond, covalently b ...
. Well-defined cluster compounds are numerous. In some cases, gold has a fractional oxidation state. A representative example is the octahedral species .


Origin


Gold production in the universe

Gold in the universe is produced through several cosmic processes and was present in the
dust Dust is made of particle size, fine particles of solid matter. On Earth, it generally consists of particles in the atmosphere that come from various sources such as soil lifted by wind (an aeolian processes, aeolian process), Types of volcan ...
from which the
Solar System The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Sola ...
formed. Scientists have identified three main cosmic sources for gold formation:
supernova nucleosynthesis Supernova nucleosynthesis is the nucleosynthesis of chemical elements in supernova explosions. In sufficiently massive stars, the nucleosynthesis by fusion of lighter elements into heavier ones occurs during sequential hydrostatic burning process ...
, neutron star collisions, and magnetar flares. All three sources involve a process called the
r-process In nuclear astrophysics, the rapid neutron-capture process, also known as the ''r''-process, is a set of nuclear reactions that is responsible for nucleosynthesis, the creation of approximately half of the Atomic nucleus, atomic nuclei Heavy meta ...
(rapid neutron capture), which forms elements heavier than
iron Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...
. For decades, scientists believed
supernova nucleosynthesis Supernova nucleosynthesis is the nucleosynthesis of chemical elements in supernova explosions. In sufficiently massive stars, the nucleosynthesis by fusion of lighter elements into heavier ones occurs during sequential hydrostatic burning process ...
was the primary mechanism for gold formation. More recently, research has shown that neutron star collisions produce significant quantities of gold through the r-process. In August 2017, the spectroscopic signatures of heavy elements, including gold, were directly observed by electromagnetic observatories during the
GW170817 GW170817 was a gravitational wave (GW) observed by the LIGO and Virgo detectors on 17 August 2017, originating within the shell elliptical galaxy NGC 4993, about 144 million light years away. The wave was produced by the last moments of the in ...
neutron star merger event. This confirmed neutron star mergers as a source of gold, after years of only indirect detection. This single event generated between 3 and 13
Earth mass An Earth mass (denoted as ''M''🜨, ''M''♁ or ''M''E, where 🜨 and ♁ are the astronomical symbols for Earth), is a unit of mass equal to the mass of the planet Earth. The current best estimate for the mass of Earth is , with a relative ...
es of gold, suggesting that neutron star mergers might produce enough gold to account for most of this element in the universe. However, neutron star mergers alone cannot explain all cosmic gold, particularly in older stars, because these mergers occur relatively late in galactic history and are infrequent (approximately once every 100,000 years). This created a timing paradox in explaining the presence of gold in stars formed early in the universe. In 2025, researchers resolved this paradox by confirming that giant flares from
magnetar A magnetar is a type of neutron star with an extremely powerful magnetic field (~109 to 1011 T, ~1013 to 1015 G). The magnetic-field decay powers the emission of high-energy electromagnetic radiation, particularly X-rays and gamma rays.Ward; Br ...
s (highly magnetic neutron stars) are also a significant source of gold formation. Analysis of a 2004 magnetar flare showed these events produce heavy elements through the same r-process as neutron star mergers. The amount of heavy elements created in a single magnetar flare can exceed the mass of Mars. Since magnetars existed earlier in cosmic history and flare more frequently than neutron star mergers occur, they help explain gold's presence in older stars. Scientists estimate magnetar flares may contribute approximately 1-10% of all elements heavier than iron in our galaxy, including gold.


Asteroid origin theories

Because the Earth was molten when it was formed, almost all of the gold present in the early Earth probably sank into the
planetary core A planetary core consists of the innermost layers of a planet. Cores may be entirely liquid, or a mixture of solid and liquid layers as is the case in the Earth. In the Solar System, core sizes range from about 20% (the Moon) to 85% of a plan ...
. Therefore, as hypothesized in one model, most of the gold in the Earth's crust and mantle is thought to have been delivered to Earth by
asteroid impact An impact event is a collision between astronomical objects causing measurable effects. Impact events have been found to regularly occur in planetary systems, though the most frequent involve asteroids, comets or meteoroids and have minimal effe ...
s during the
Late Heavy Bombardment The Late Heavy Bombardment (LHB), or lunar cataclysm, is a hypothesized astronomical event thought to have occurred approximately 4.1 to 3.8 billion years (Ga) ago, at a time corresponding to the Neohadean and Eoarchean eras on Earth. According ...
, about 4 billion years ago. Gold which is reachable by humans has, in one case, been associated with a particular asteroid impact. The asteroid that formed
Vredefort impact structure The Vredefort impact structure is one of the largest impact structures on Earth. The crater, which has since been eroded away, has been estimated at across when it was formed, the latter estimate suggesting the initial crater was larger than ...
2.020 billion years ago is often credited with seeding the
Witwatersrand basin The Witwatersrand (, ; ; locally the Rand or, less commonly, the Reef) is a , north-facing scarp in South Africa. It consists of a hard, erosion-resistant quartzite metamorphic rock, over which several north-flowing rivers form waterfalls, wh ...
in
South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...
with the richest gold deposits on earth. However, this scenario is now questioned. The gold-bearing
Witwatersrand The Witwatersrand (, ; ; locally the Rand or, less commonly, the Reef) is a , north-facing scarp in South Africa. It consists of a hard, erosion-resistant quartzite metamorphic rock, over which several north-flowing rivers form waterfalls, w ...
rocks were laid down between 700 and 950 million years before the Vredefort impact.McCarthy, T., Rubridge, B. (2005). ''The Story of Earth and Life''. Struik Publishers, Cape Town. pp. 89–90, 102–107, 134–136. Norman, N., Whitfield, G. (2006) ''Geological Journeys''. Struik Publishers, Cape Town. pp. 38–49, 60–61. These gold-bearing rocks had furthermore been covered by a thick layer of Ventersdorp lavas and the Transvaal Supergroup of rocks before the meteor struck, and thus the gold did not actually arrive in the asteroid/meteorite. What the Vredefort impact achieved, however, was to distort the
Witwatersrand basin The Witwatersrand (, ; ; locally the Rand or, less commonly, the Reef) is a , north-facing scarp in South Africa. It consists of a hard, erosion-resistant quartzite metamorphic rock, over which several north-flowing rivers form waterfalls, wh ...
in such a way that the gold-bearing rocks were brought to the present
erosion surface In geology and geomorphology, an erosion surface is a surface of rock (geology), rock or regolith that was formed by erosion and not by construction (e.g. lava flows, sediment deposition) nor fault (geology), fault displacement. Erosional surfaces ...
in
Johannesburg Johannesburg ( , , ; Zulu language, Zulu and Xhosa language, Xhosa: eGoli ) (colloquially known as Jozi, Joburg, Jo'burg or "The City of Gold") is the most populous city in South Africa. With 5,538,596 people in the City of Johannesburg alon ...
, on the
Witwatersrand The Witwatersrand (, ; ; locally the Rand or, less commonly, the Reef) is a , north-facing scarp in South Africa. It consists of a hard, erosion-resistant quartzite metamorphic rock, over which several north-flowing rivers form waterfalls, w ...
, just inside the rim of the original diameter crater caused by the meteor strike. The discovery of the deposit in 1886 launched the
Witwatersrand Gold Rush The Witwatersrand Gold Rush was a gold rush that began in 1886 and led to the establishment of Johannesburg, South Africa. It was a part of the Mineral Revolution. Origins In the modern-day province of Mpumalanga, gold miners in the alluvial ...
. Some 22% of all the gold that is ascertained to exist today on Earth has been extracted from these Witwatersrand rocks.


Mantle return theories

Much of the rest of the gold on Earth is thought to have been incorporated into the planet since its very beginning, as
planetesimals Planetesimals () are solid objects thought to exist in protoplanetary disks and debris disks. Believed to have formed in the Solar System about 4.6 billion years ago, they aid study of its formation. Formation A widely accepted theory of pla ...
formed the mantle. In 2017, an international group of scientists established that gold "came to the Earth's surface from the deepest regions of our planet", the mantle, as evidenced by their findings at Deseado Massif in the Argentinian Patagonia.


Occurrence

On Earth, gold is found in
ore Ore is natural rock or sediment that contains one or more valuable minerals, typically including metals, concentrated above background levels, and that is economically viable to mine and process. The grade of ore refers to the concentration ...
s in rock formed from the
Precambrian The Precambrian ( ; or pre-Cambrian, sometimes abbreviated pC, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of t ...
time onward. It most often occurs as a
native metal A native metal is any metal that is found pure in its metallic form in nature. Metals that can be found as native element mineral, native deposits singly or in alloys include antimony, arsenic, bismuth, cadmium, chromium, cobalt, indium, iron, ma ...
, typically in a metal
solid solution A solid solution, a term popularly used for metals, is a homogeneous mixture of two compounds in solid state and having a single crystal structure. Many examples can be found in metallurgy, geology, and solid-state chemistry. The word "solutio ...
with silver (i.e. as a gold/silver
alloy An alloy is a mixture of chemical elements of which in most cases at least one is a metal, metallic element, although it is also sometimes used for mixtures of elements; herein only metallic alloys are described. Metallic alloys often have prop ...
). Such alloys usually have a silver content of 8–10%.
Electrum Electrum is a naturally occurring alloy of gold and silver, with trace amounts of copper and other metals. Its color ranges from pale to bright yellow, depending on the proportions of gold and silver. It has been produced artificially and is ...
is elemental gold with more than 20% silver, and is commonly known as
white gold White gold is an alloy of gold and at least one white metal, usually nickel or palladium. Like yellow gold, the purity of white gold is given in carats (karats). It is often used on jewellery. A common white gold formulation consists of 90% wt ...
. Electrum's color runs from golden-silvery to silvery, dependent upon the silver content. The more silver, the lower the
specific gravity Relative density, also called specific gravity, is a dimensionless quantity defined as the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for solids and liquids is nea ...
. Native gold occurs as very small to microscopic particles embedded in rock, often together with
quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...
or
sulfide mineral The sulfide minerals are a class of minerals containing sulfide (S2−) or disulfide () as the major anion. Some sulfide minerals are economically important as metal ores. The sulfide class also includes the selenide mineral, selenides, the tell ...
s such as "
fool's gold The mineral pyrite ( ), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Iron, FeSulfur, S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic Lustre (mineralogy), lu ...
", which is a
pyrite The mineral pyrite ( ), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic luster and pale brass-yellow hue ...
. These are called
lode In geology, a lode is a deposit of metalliferous ore that fills or is embedded in a fracture (or crack) in a rock formation or a vein of ore that is deposited or embedded between layers of rock. The current meaning (ore vein) dates from th ...
deposits. The metal in a native state is also found in the form of free flakes, grains or larger nuggets that have been eroded from rocks and end up in
alluvial Alluvium (, ) is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluvium is also sometimes called alluvial deposit. Alluvium is ...
deposits called
placer deposit In geology, a placer deposit or placer is an accumulation of valuable minerals formed by gravity separation from a specific source rock during sedimentary processes. The name is from the Spanish language, Spanish word ''placer'', meaning "alluviu ...
s. Such free gold is always richer at the exposed surface of gold-bearing veins, owing to the
oxidation Redox ( , , reduction–oxidation or oxidation–reduction) is a type of chemical reaction in which the oxidation states of the reactants change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is ...
of accompanying minerals followed by weathering; and by washing of the dust into streams and rivers, where it collects and can be welded by water action to form nuggets. Gold sometimes occurs combined with
tellurium Tellurium is a chemical element; it has symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally fou ...
as the
mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): Mi ...
s
calaverite Calaverite, or gold telluride, is an uncommon telluride (chemistry), telluride of gold, a metallic mineral with the chemical formula AuTe2, with approximately 3% of the gold Silver telluride, replaced by silver. It was first discovered in Calave ...
,
krennerite Krennerite is an orthorhombic gold telluride mineral which can contain variable amounts of silver in the structure. The formula is AuTe2, but specimen with gold substituted by up to 24% with silver have been found ( u0.77Ag0.24e2). Both of the c ...
, nagyagite, petzite and
sylvanite Sylvanite or silver gold telluride, chemical formula , is the most common telluride of gold. Properties The gold:silver ratio varies from 3:1 to 1:1. It is a metallic mineral with a color that ranges from a steely gray to almost white. It is c ...
(see
telluride mineral A telluride mineral is a mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure for ...
s), and as the rare bismuthide maldonite () and antimonide
aurostibite Aurostibite is an isometric gold antimonide mineral which is a member of the pyrite group. Aurostibite was discovered in 1952 and can be found in hydrothermal gold-quartz veins, in sulfur-deficient environments that contain other antimony miner ...
(). Gold also occurs in rare alloys with
copper Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...
,
lead Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...
, and mercury: the minerals auricupride (), novodneprite () and weishanite (). A 2004 research paper suggests that microbes can sometimes play an important role in forming gold deposits, transporting and precipitating gold to form grains and nuggets that collect in alluvial deposits. A 2013 study has claimed water in faults vaporizes during an earthquake, depositing gold. When an earthquake strikes, it moves along a fault. Water often lubricates faults, filling in fractures and jogs. About below the surface, under very high temperatures and pressures, the water carries high concentrations of carbon dioxide, silica, and gold. During an earthquake, the fault jog suddenly opens wider. The water inside the void instantly vaporizes, flashing to steam and forcing silica, which forms the mineral quartz, and gold out of the fluids and onto nearby surfaces.


Seawater

The world's
ocean The ocean is the body of salt water that covers approximately 70.8% of Earth. The ocean is conventionally divided into large bodies of water, which are also referred to as ''oceans'' (the Pacific, Atlantic, Indian Ocean, Indian, Southern Ocean ...
s contain gold. Measured concentrations of gold in the Atlantic and Northeast Pacific are 50–150 femtomol/L or 10–30 parts per
quadrillion Depending on context (e.g. language, culture, region), some large numbers have names that allow for describing large quantities in a textual form; not mathematical. For very large values, the text is generally shorter than a decimal numeric repres ...
(about 10–30 g/km3). In general, gold concentrations for south Atlantic and central Pacific samples are the same (~50 femtomol/L) but less certain. Mediterranean deep waters contain slightly higher concentrations of gold (100–150 femtomol/L), which is attributed to wind-blown dust or rivers. At 10 parts per quadrillion, the Earth's
oceans The ocean is the body of salt water that covers approximately 70.8% of Earth. The ocean is conventionally divided into large bodies of water, which are also referred to as ''oceans'' (the Pacific, Atlantic, Indian, Antarctic/Southern, and ...
would hold 15,000 tonnes of gold. These figures are three orders of magnitude less than reported in the literature prior to 1988, indicating contamination problems with the earlier data. A number of people have claimed to be able to economically recover gold from
sea water Seawater, or sea water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, 35 ppt, 600 mM). This means that every kilogram (roughly one liter by volume) of seawater has approximate ...
, but they were either mistaken or acted in an intentional deception.
Prescott Jernegan Lubec ( ) is a town in Washington County, Maine, United States. It is the easternmost municipality in the contiguous U.S. (see List of extreme points of the United States, extreme points of the United States) and is the country's closest contine ...
ran a gold-from-seawater swindle in the
United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
in the 1890s, as did an English fraudster in the early 1900s.
Fritz Haber Fritz Jakob Haber (; 9 December 1868 – 29 January 1934) was a German chemist who received the Nobel Prize in Chemistry in 1918 for his invention of the Haber process, a method used in industry to synthesize ammonia from nitrogen gas and hydrog ...
did research on the extraction of gold from sea water in an effort to help pay
Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...
's reparations following
World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
. Based on the published values of 2 to 64 ppb of gold in seawater, a commercially successful extraction seemed possible. After analysis of 4,000 water samples yielding an average of 0.004 ppb, it became clear that extraction would not be possible, and he ended the project.


History

The earliest recorded metal employed by humans appears to be gold, which can be found free or "
native Native may refer to: People * '' Jus sanguinis'', nationality by blood * '' Jus soli'', nationality by location of birth * Indigenous peoples, peoples with a set of specific rights based on their historical ties to a particular territory ** Nat ...
". Small amounts of natural gold have been found in Spanish caves used during the late
Paleolithic The Paleolithic or Palaeolithic ( years ago) ( ), also called the Old Stone Age (), is a period in human prehistory that is distinguished by the original development of stone tools, and which represents almost the entire period of human prehist ...
period, . The oldest gold artifacts in the world are from
Bulgaria Bulgaria, officially the Republic of Bulgaria, is a country in Southeast Europe. It is situated on the eastern portion of the Balkans directly south of the Danube river and west of the Black Sea. Bulgaria is bordered by Greece and Turkey t ...
and are dating back to the 5th millennium BC (4,600 BC to 4,200 BC), such as those found in the
Varna Necropolis The Varna Necropolis (), or Varna Cemetery, is a burial site in the western industrial zone of Varna, Bulgaria, Varna (approximately half a kilometre from Lake Varna and 4 km from the city centre), internationally considered one of the key a ...
near Lake Varna and the
Black Sea The Black Sea is a marginal sea, marginal Mediterranean sea (oceanography), mediterranean sea lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bound ...
coast, thought to be the earliest "well-dated" finding of gold artifacts in history. Gold artifacts probably made their first appearance in Ancient Egypt at the very beginning of the pre-dynastic period, at the end of the fifth millennium BC and the start of the fourth, and smelting was developed during the course of the 4th millennium; gold artifacts appear in the archeology of Lower Mesopotamia during the early 4th millennium. As of 1990, gold artifacts found at the
Wadi Qana Wadi Qana (, ) is a wadi with an intermittent stream meandering westwards from Huwara, south of Nablus, in the West Bank, Palestine, down to Jaljulia in Israel, from where it flows into the Yarkon River, of which it is a tributary. Geog ...
cave cemetery of the
4th millennium BC File:4th millennium BC montage.jpg, 400x400px, From top left clockwise: The Temple of Ġgantija, one of the oldest freestanding structures in the world; Warka Vase; Bronocice pot with one of the earliest known depictions of a wheeled vehicle; Kish ...
in
West Bank The West Bank is located on the western bank of the Jordan River and is the larger of the two Palestinian territories (the other being the Gaza Strip) that make up the State of Palestine. A landlocked territory near the coast of the Mediter ...
were the earliest from the Levant. Gold artifacts such as the golden hats and the Nebra disk appeared in Central Europe from the 2nd millennium BC
Bronze Age The Bronze Age () was a historical period characterised principally by the use of bronze tools and the development of complex urban societies, as well as the adoption of writing in some areas. The Bronze Age is the middle principal period of ...
. The oldest known map of a gold mine was drawn in the 19th Dynasty of Ancient Egypt (1320–1200 BC), whereas the first written reference to gold was recorded in the 12th Dynasty around 1900 BC.
Egyptian hieroglyph Ancient Egyptian hieroglyphs ( ) were the formal writing system used in Ancient Egypt for writing the Egyptian language. Hieroglyphs combined ideographic, logographic, syllabic and alphabetic elements, with more than 1,000 distinct characters. ...
s from as early as 2600 BC describe gold, which King
Tushratta Tushratta ( Akkadian: and ) was a king of Mitanni, 1358–1335 BCE, at the end of the reign of Amenhotep III and throughout the first half the reign of Akhenaten. He was the son of Shuttarna II. Tushratta stated that he was the grandson of A ...
of the
Mitanni Mitanni (–1260 BC), earlier called Ḫabigalbat in old Babylonian texts, ; Hanigalbat or Hani-Rabbat in Assyrian records, or in Ancient Egypt, Egyptian texts, was a Hurrian language, Hurrian-speaking state in northern Syria (region), Syria an ...
claimed was "more plentiful than dirt" in Egypt. Egypt and especially
Nubia Nubia (, Nobiin language, Nobiin: , ) is a region along the Nile river encompassing the area between the confluence of the Blue Nile, Blue and White Nile, White Niles (in Khartoum in central Sudan), and the Cataracts of the Nile, first cataract ...
had the resources to make them major gold-producing areas for much of history. One of the earliest known maps, known as the
Turin Papyrus Map The Turin Papyrus Map is an ancient Egyptian map, generally considered the oldest surviving map of topographical interest from the ancient world. It is drawn on a papyrus reportedly discovered at Deir el-Medina in Thebes, collected by Bernardin ...
, shows the plan of a
gold mine Gold mining is the extraction of gold by mining. Historically, mining gold from alluvial deposits used manual separation processes, such as gold panning. The expansion of gold mining to ores that are not on the surface has led to more comple ...
in Nubia together with indications of the local
geology Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth ...
. The primitive working methods are described by both
Strabo Strabo''Strabo'' (meaning "squinty", as in strabismus) was a term employed by the Romans for anyone whose eyes were distorted or deformed. The father of Pompey was called "Gnaeus Pompeius Strabo, Pompeius Strabo". A native of Sicily so clear-si ...
and
Diodorus Siculus Diodorus Siculus or Diodorus of Sicily (;  1st century BC) was an ancient Greece, ancient Greek historian from Sicily. He is known for writing the monumental Universal history (genre), universal history ''Bibliotheca historica'', in forty ...
, and included
fire-setting Fire-setting is a method of traditional mining used most commonly from prehistoric times up to the Middle Ages. Fires were set against a rock face to heat the stone, which was then doused with liquid, causing the stone to fracture by thermal s ...
. Large mines were also present across the
Red Sea The Red Sea is a sea inlet of the Indian Ocean, lying between Africa and Asia. Its connection to the ocean is in the south, through the Bab-el-Mandeb Strait and the Gulf of Aden. To its north lie the Sinai Peninsula, the Gulf of Aqaba, and th ...
in what is now
Saudi Arabia Saudi Arabia, officially the Kingdom of Saudi Arabia (KSA), is a country in West Asia. Located in the centre of the Middle East, it covers the bulk of the Arabian Peninsula and has a land area of about , making it the List of Asian countries ...
. Gold is mentioned in the Amarna letters numbered 19 and 26 from around the 14th century BC. Gold is mentioned frequently in the
Old Testament The Old Testament (OT) is the first division of the Christian biblical canon, which is based primarily upon the 24 books of the Hebrew Bible, or Tanakh, a collection of ancient religious Hebrew and occasionally Aramaic writings by the Isr ...
, starting with
Genesis Genesis may refer to: Religion * Book of Genesis, the first book of the biblical scriptures of both Judaism and Christianity, describing the creation of the Earth and of humankind * Genesis creation narrative, the first several chapters of the Bo ...
2:11 (at
Havilah Havilah () refers to both a land and people in several books of the Bible; one is mentioned in Genesis 2:10–11, while the other is mentioned in the Generations of Noah (Genesis 10:7). In Genesis 2:10–11, Havilah is associated with the Garden ...
), the story of the
golden calf According to the Torah, the Bible, and the Quran, the golden calf () was a cult image made by the Israelites when Moses went up to Mount Sinai (bible), Mount Sinai. In Hebrew, the incident is known as "the sin of the calf" (). It is first mentio ...
, and many parts of the temple including the Menorah and the golden altar. In the
New Testament The New Testament (NT) is the second division of the Christian biblical canon. It discusses the teachings and person of Jesus in Christianity, Jesus, as well as events relating to Christianity in the 1st century, first-century Christianit ...
, it is included with the gifts of the
magi Magi (), or magus (), is the term for priests in Zoroastrianism and earlier Iranian religions. The earliest known use of the word ''magi'' is in the trilingual inscription written by Darius the Great, known as the Behistun Inscription. Old Per ...
in the first chapters of Matthew. The
Book of Revelation The Book of Revelation, also known as the Book of the Apocalypse or the Apocalypse of John, is the final book of the New Testament, and therefore the final book of the Bible#Christian Bible, Christian Bible. Written in Greek language, Greek, ...
21:21 describes the city of
New Jerusalem In the Book of Ezekiel in the Hebrew Bible, New Jerusalem (, ''YHWH šāmmā'', YHWH sthere") is Ezekiel's prophetic vision of a city centered on the rebuilt Holy Temple, to be established in Jerusalem, which would be the capital of the ...
as having streets "made of pure gold, clear as crystal". Exploitation of gold in the south-east corner of the
Black Sea The Black Sea is a marginal sea, marginal Mediterranean sea (oceanography), mediterranean sea lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bound ...
is said to date from the time of
Midas Midas (; ) was a king of Phrygia with whom many myths became associated, as well as two later members of the Phrygian royal house. His father was Gordias, and his mother was Cybele. The most famous King Midas is popularly remembered in Greek m ...
, and this gold was important in the establishment of what is probably the world's earliest coinage in
Lydia Lydia (; ) was an Iron Age Monarchy, kingdom situated in western Anatolia, in modern-day Turkey. Later, it became an important province of the Achaemenid Empire and then the Roman Empire. Its capital was Sardis. At some point before 800 BC, ...
around 610 BC. The legend of the golden fleece dating from eighth century BCE may refer to the use of fleeces to trap gold dust from
placer deposit In geology, a placer deposit or placer is an accumulation of valuable minerals formed by gravity separation from a specific source rock during sedimentary processes. The name is from the Spanish language, Spanish word ''placer'', meaning "alluviu ...
s in the ancient world. From the 6th or 5th century BC, the
Chu (state) Chu (, Old Chinese: ''*s-r̥aʔ'') was an Ancient Chinese states, ancient Chinese state during the Zhou dynasty. Their first ruler was King Wu of Chu in the early 8th century BC. Chu was located in the south of the Zhou heartland and lasted ...
circulated the Ying Yuan, one kind of square gold coin. In
Roman metallurgy Metals and metal working had been known to the people of modern Italy since the Bronze Age. By 53 BC, Rome had expanded to control an immense expanse of the Mediterranean. This included Italy and its islands, Spain, Macedonia, Africa, Asia ...
, new methods for extracting gold on a large scale were developed by introducing
hydraulic mining Hydraulic mining is a form of mining that uses high-pressure jets of water to dislodge rock material or move sediment.Paul W. Thrush, ''A Dictionary of Mining, Mineral, and Related Terms'', US Bureau of Mines, 1968, p.560. In the placer mining of ...
methods, especially in
Hispania Hispania was the Ancient Rome, Roman name for the Iberian Peninsula. Under the Roman Republic, Hispania was divided into two Roman province, provinces: Hispania Citerior and Hispania Ulterior. During the Principate, Hispania Ulterior was divide ...
from 25 BC onwards and in
Dacia Dacia (, ; ) was the land inhabited by the Dacians, its core in Transylvania, stretching to the Danube in the south, the Black Sea in the east, and the Tisza in the west. The Carpathian Mountains were located in the middle of Dacia. It thus ro ...
from 106 AD onwards. One of their largest mines was at Las Medulas in León, where seven long aqueducts enabled them to sluice most of a large alluvial deposit. The mines at Roşia Montană in
Transylvania Transylvania ( or ; ; or ; Transylvanian Saxon dialect, Transylvanian Saxon: ''Siweberjen'') is a List of historical regions of Central Europe, historical and cultural region in Central Europe, encompassing central Romania. To the east and ...
were also very large, and until very recently, still mined by opencast methods. They also exploited smaller deposits in
Britain Britain most often refers to: * Great Britain, a large island comprising the countries of England, Scotland and Wales * The United Kingdom of Great Britain and Northern Ireland, a sovereign state in Europe comprising Great Britain and the north-eas ...
, such as placer and hard-rock deposits at
Dolaucothi The Dolaucothi Gold Mines (; ) (), also known as the Ogofau Gold Mine, are ancient Roman surface and underground mines located in the valley of the River Cothi, near Pumsaint, Carmarthenshire, Wales. The gold mines are located within the ...
. The various methods they used are well described by
Pliny the Elder Gaius Plinius Secundus (AD 23/24 79), known in English as Pliny the Elder ( ), was a Roman Empire, Roman author, Natural history, naturalist, and naval and army commander of the early Roman Empire, and a friend of the Roman emperor, emperor Vesp ...
in his
encyclopedia An encyclopedia is a reference work or compendium providing summaries of knowledge, either general or special, in a particular field or discipline. Encyclopedias are divided into article (publishing), articles or entries that are arranged Alp ...
''
Naturalis Historia The ''Natural History'' () is a Latin work by Pliny the Elder. The largest single work to have survived from the Roman Empire to the modern day, the ''Natural History'' compiles information gleaned from other ancient authors. Despite the work' ...
'' written towards the end of the first century AD. During
Mansa Musa Mansa Musa (reigned ) was the ninth '' Mansa'' of the Mali Empire, which reached its territorial peak during his reign. Musa's reign is often regarded as the zenith of Mali's power and prestige, although he features less in Mandinka oral tradit ...
's (ruler of the
Mali Empire The Mali Empire (Manding languages, Manding: ''Mandé''Ki-Zerbo, Joseph: ''UNESCO General History of Africa, Vol. IV, Abridged Edition: Africa from the Twelfth to the Sixteenth Century'', p. 57. University of California Press, 1997. or ''Manden ...
from 1312 to 1337)
hajj Hajj (; ; also spelled Hadj, Haj or Haji) is an annual Islamic pilgrimage to Mecca, Saudi Arabia, the holiest city for Muslims. Hajj is a mandatory religious duty for capable Muslims that must be carried out at least once in their lifetim ...
to
Mecca Mecca, officially Makkah al-Mukarramah, is the capital of Mecca Province in the Hejaz region of western Saudi Arabia; it is the Holiest sites in Islam, holiest city in Islam. It is inland from Jeddah on the Red Sea, in a narrow valley above ...
in 1324, he passed through
Cairo Cairo ( ; , ) is the Capital city, capital and largest city of Egypt and the Cairo Governorate, being home to more than 10 million people. It is also part of the List of urban agglomerations in Africa, largest urban agglomeration in Africa, L ...
in July 1324, and was reportedly accompanied by a
camel train A camel train, caravan, or camel string is a series of camels carrying passengers and goods on a regular or semi-regular service between points. Despite rarely travelling faster than human walking speed, for centuries camels' ability to withst ...
that included thousands of people and nearly a hundred camels where he gave away so much gold that it depressed the price in Egypt for over a decade, causing high
inflation In economics, inflation is an increase in the average price of goods and services in terms of money. This increase is measured using a price index, typically a consumer price index (CPI). When the general price level rises, each unit of curre ...
. A contemporary Arab historian remarked: The European exploration of the Americas was fueled in no small part by reports of the gold ornaments displayed in great profusion by Native American peoples, especially in
Mesoamerica Mesoamerica is a historical region and cultural area that begins in the southern part of North America and extends to the Pacific coast of Central America, thus comprising the lands of central and southern Mexico, all of Belize, Guatemala, El S ...
,
Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...
,
Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...
and
Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...
. The
Aztec The Aztecs ( ) were a Mesoamerican civilization that flourished in central Mexico in the Post-Classic stage, post-classic period from 1300 to 1521. The Aztec people included different Indigenous peoples of Mexico, ethnic groups of central ...
s regarded gold as the product of the gods, calling it literally "god excrement" (''teocuitlatl'' in
Nahuatl Nahuatl ( ; ), Aztec, or Mexicano is a language or, by some definitions, a group of languages of the Uto-Aztecan language family. Varieties of Nahuatl are spoken by about Nahuas, most of whom live mainly in Central Mexico and have smaller popul ...
), and after
Moctezuma II Moctezuma Xocoyotzin . ( – 29 June 1520), retroactively referred to in European sources as Moctezuma II, and often simply called Montezuma,Other variant spellings include Moctezuma, Motewksomah, Motecuhzomatzin, Moteuczoma, Motecuhzoma, Motē ...
was killed, most of this gold was shipped to Spain. However, for the
indigenous peoples of North America In the Americas, Indigenous peoples comprise the two continents' pre-Columbian inhabitants, as well as the ethnic groups that identify with them in the 15th century, as well as the ethnic groups that identify with the pre-Columbian population of ...
gold was considered useless and they saw much greater value in other
minerals In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2011): M ...
which were directly related to their utility, such as
obsidian Obsidian ( ) is a naturally occurring volcanic glass formed when lava extrusive rock, extruded from a volcano cools rapidly with minimal crystal growth. It is an igneous rock. Produced from felsic lava, obsidian is rich in the lighter element ...
,
flint Flint, occasionally flintstone, is a sedimentary cryptocrystalline form of the mineral quartz, categorized as the variety of chert that occurs in chalk or marly limestone. Historically, flint was widely used to make stone tools and start ...
, and
slate Slate is a fine-grained, foliated, homogeneous, metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade, regional metamorphism. It is the finest-grained foliated metamorphic ro ...
.
El Dorado El Dorado () is a mythical city of gold supposedly located somewhere in South America. The king of this city was said to be so rich that he would cover himself from head to foot in gold dust – either daily or on certain ceremonial occasions � ...
is applied to a legendary story in which precious stones were found in fabulous abundance along with gold coins. The concept of El Dorado underwent several transformations, and eventually accounts of the previous myth were also combined with those of a legendary lost city. El Dorado, was the term used by the Spanish Empire to describe a mythical tribal chief (zipa) of the Muisca native people in
Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...
, who, as an initiation rite, covered himself with gold dust and submerged in Lake Guatavita. The legends surrounding El Dorado changed over time, as it went from being a man, to a city, to a kingdom, and then finally to an empire. Beginning in the
early modern period The early modern period is a Periodization, historical period that is defined either as part of or as immediately preceding the modern period, with divisions based primarily on the history of Europe and the broader concept of modernity. There i ...
, European
exploration Exploration is the process of exploring, an activity which has some Expectation (epistemic), expectation of Discovery (observation), discovery. Organised exploration is largely a human activity, but exploratory activity is common to most organis ...
and
colonization 475px, Map of the year each country achieved List of sovereign states by date of formation, independence. Colonization (British English: colonisation) is a process of establishing occupation of or control over foreign territories or peoples f ...
of
West Africa West Africa, also known as Western Africa, is the westernmost region of Africa. The United Nations geoscheme for Africa#Western Africa, United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Gha ...
was driven in large part by reports of gold deposits in the region, which was eventually referred to by Europeans as the " Gold Coast". From the late 15th to early 19th centuries, European trade in the region was primarily focused in gold, along with
ivory Ivory is a hard, white material from the tusks (traditionally from elephants) and Tooth, teeth of animals, that consists mainly of dentine, one of the physical structures of teeth and tusks. The chemical structure of the teeth and tusks of mamm ...
and
slaves Slavery is the ownership of a person as property, especially in regards to their labour. Slavery typically involves compulsory work, with the slave's location of work and residence dictated by the party that holds them in bondage. Enslavemen ...
. The gold trade in West Africa was dominated by the
Ashanti Empire The Asante Empire ( Asante Twi: ), also known as the Ashanti Empire, was an Akan state that lasted from 1701 to 1901, in what is now modern-day Ghana. It expanded from the Ashanti Region to include most of Ghana and also parts of Ivory Coast ...
, who initially traded with the Portuguese before branching out and trading with
British British may refer to: Peoples, culture, and language * British people, nationals or natives of the United Kingdom, British Overseas Territories and Crown Dependencies. * British national identity, the characteristics of British people and culture ...
, French,
Spanish Spanish might refer to: * Items from or related to Spain: **Spaniards are a nation and ethnic group indigenous to Spain **Spanish language, spoken in Spain and many countries in the Americas **Spanish cuisine **Spanish history **Spanish culture ...
and Danish merchants. British desires to secure control of West African gold deposits played a role in the
Anglo-Ashanti wars The Anglo-Ashanti wars were a series of five conflicts that took place between 1824 and 1900 between the Ashanti Empire—in the Akan people, Akan interior of the Gold Coast (British colony), Gold Coast—and the British Empire and its African ...
of the late 19th century, which saw the Ashanti Empire annexed by Britain. Gold played a role in western culture, as a cause for desire and of corruption, as told in children's
fable Fable is a literary genre defined as a succinct fictional story, in prose or verse, that features animals, legendary creatures, plants, inanimate objects, or forces of nature that are anthropomorphized, and that illustrates or leads to a parti ...
s such as
Rumpelstiltskin "Rumpelstiltskin" ( ; ) is a German fairy tale collected by the Brothers Grimm in the 1812 edition of ''Children's and Household Tales''. The story is about an imp who spins straw into gold in exchange for a woman's firstborn child. Plot I ...
—where Rumpelstiltskin turns hay into gold for the peasant's daughter in return for her child when she becomes a princess—and the stealing of the hen that lays golden eggs in
Jack and the Beanstalk "Jack and the Beanstalk" is an English fairy tale with ancient origins. It appeared as "The Story of Jack Spriggins and the Enchanted Bean" in 1734 4th edition :File:Round about our Coal Fire, or, Christmas Entertainments, 4th edn, 1734.pdf, On C ...
. The top prize at the
Olympic Games The modern Olympic Games (Olympics; ) are the world's preeminent international Olympic sports, sporting events. They feature summer and winter sports competitions in which thousands of athletes from around the world participate in a Multi-s ...
and many other sports competitions is the
gold medal A gold medal is a medal awarded for highest achievement in a non-military field. Its name derives from the use of at least a fraction of gold in form of plating or alloying in its manufacture. Since the eighteenth century, gold medals have b ...
. 75% of the presently accounted for gold has been extracted since 1910, two-thirds since 1950. One main goal of the
alchemists Alchemy (from the Arabic word , ) is an ancient branch of natural philosophy, a philosophical and protoscientific tradition that was historically practised in China, India, the Muslim world, and Europe. In its Western form, alchemy is first ...
was to produce gold from other substances, such as
lead Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...
 — presumably by the interaction with a mythical substance called the
philosopher's stone The philosopher's stone is a mythic alchemical substance capable of turning base metals such as mercury into gold or silver; it was also known as "the tincture" and "the powder". Alchemists additionally believed that it could be used to mak ...
. Trying to produce gold led the alchemists to systematically find out what can be done with substances, and this laid the foundation for today's
chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a physical science within the natural sciences that studies the chemical elements that make up matter and chemical compound, compounds made of atoms, molecules a ...
, which can produce gold (albeit uneconomically) by using
nuclear transmutation Nuclear transmutation is the conversion of one chemical element or an isotope into another chemical element. Nuclear transmutation occurs in any process where the number of protons or neutrons in the nucleus of an atom is changed. A transmutat ...
. Their symbol for gold was the circle with a point at its center (☉), which was also the
astrological Astrology is a range of divinatory practices, recognized as pseudoscientific since the 18th century, that propose that information about human affairs and terrestrial events may be discerned by studying the apparent positions of celesti ...
symbol and the ancient
Chinese character Chinese characters are logographs used to write the Chinese languages and others from regions historically influenced by Chinese culture. Of the four independently invented writing systems accepted by scholars, they represent the only on ...
for the
Sun The Sun is the star at the centre of the Solar System. It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light a ...
. The
Dome of the Rock The Dome of the Rock () is an Islamic shrine at the center of the Al-Aqsa mosque compound on the Temple Mount in the Old City (Jerusalem), Old City of Jerusalem. It is the world's oldest surviving work of Islamic architecture, the List_of_the_ol ...
is covered with an ultra-thin golden glassier. The
Sikh Sikhs (singular Sikh: or ; , ) are an ethnoreligious group who adhere to Sikhism, a religion that originated in the late 15th century in the Punjab region of the Indian subcontinent, based on the revelation of Guru Nanak. The term ''Si ...
Golden temple, the
Harmandir Sahib The Golden Temple is a gurdwara located in Amritsar, Punjab, India. It is the pre-eminent spiritual site of Sikhism. It is one of the Holy place, holiest sites in Sikhism, alongside the Gurdwara Darbar Sahib Kartarpur in Kartarpur, Pakistan, ...
, is a building covered with gold. Similarly the
Wat Phra Kaew Wat Phra Kaew (, , ), commonly known in English as the Temple of the Emerald Buddha and officially as Wat Phra Si Rattana Satsadaram, is regarded as the most sacred Wat, Buddhist temple in Thailand. The complex consists of a number of buildings ...
emerald
Buddhist Buddhism, also known as Buddhadharma and Dharmavinaya, is an Indian religion and List of philosophies, philosophical tradition based on Pre-sectarian Buddhism, teachings attributed to the Buddha, a wandering teacher who lived in the 6th or ...
temple A temple (from the Latin ) is a place of worship, a building used for spiritual rituals and activities such as prayer and sacrifice. By convention, the specially built places of worship of some religions are commonly called "temples" in Engli ...
(
wat A wat (, ; , ; , ; ; , ) is a type of Buddhist and Hindu temple in Cambodia, Laos, East Shan State (Myanmar), Yunnan (China), the Southern Province of Sri Lanka, and Thailand. Etymology The word ''wat'' is borrowed from the Sanskrit ''v ...
) in
Thailand Thailand, officially the Kingdom of Thailand and historically known as Siam (the official name until 1939), is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. With a population of almost 66 million, it spa ...
has ornamental gold-leafed statues and roofs. Some European king and queen's crowns were made of gold, and gold was used for the bridal crown since antiquity. An ancient Talmudic text circa 100 AD describes Rachel, wife of Rabbi Akiva, receiving a "Jerusalem of Gold" (diadem). A Greek burial crown made of gold was found in a grave circa 370 BC. Gold leaf MET DP260372.jpg,
Minoan The Minoan civilization was a Bronze Age culture which was centered on the island of Crete. Known for its monumental architecture and Minoan art, energetic art, it is often regarded as the first civilization in Europe. The ruins of the Minoan pa ...
jewellery, 2300–2100 BC, gold,
Metropolitan Museum of Art The Metropolitan Museum of Art, colloquially referred to as the Met, is an Encyclopedic museum, encyclopedic art museum in New York City. By floor area, it is the List of largest museums, third-largest museum in the world and the List of larg ...
, New York Earrings from Shulgi.JPG,
Sumer Sumer () is the earliest known civilization, located in the historical region of southern Mesopotamia (now south-central Iraq), emerging during the Chalcolithic and Early Bronze Age, early Bronze Ages between the sixth and fifth millennium BC. ...
ian earrings with
cuneiform Cuneiform is a Logogram, logo-Syllabary, syllabic writing system that was used to write several languages of the Ancient Near East. The script was in active use from the early Bronze Age until the beginning of the Common Era. Cuneiform script ...
inscriptions, 2093–2046 BC, gold, Sulaymaniyah Museum,
Sulaymaniyah Sulaymaniyah or Slemani (; ), is a city in the east of the Kurdistan Region of Iraq and is the capital of the Sulaymaniyah Governorate. It is surrounded by the Azmar (Ezmer), Goizha (Goyje) and Qaiwan (Qeywan) Mountains in the northeast, Bara ...
, Iraq File:Aegina treasure 10.jpg, Minoan cup, part of the Aegina Treasure, 1850–1550 BC, gold,
British Museum The British Museum is a Museum, public museum dedicated to human history, art and culture located in the Bloomsbury area of London. Its permanent collection of eight million works is the largest in the world. It documents the story of human cu ...
Statuette of Amun MET DT553.jpg,
Ancient Egypt Ancient Egypt () was a cradle of civilization concentrated along the lower reaches of the Nile River in Northeast Africa. It emerged from prehistoric Egypt around 3150BC (according to conventional Egyptian chronology), when Upper and Lower E ...
ian statuette of
Amun Amun was a major ancient Egyptian deity who appears as a member of the Hermopolitan Ogdoad. Amun was attested from the Old Kingdom together with his wife Amunet. His oracle in Siwa Oasis, located in Western Egypt near the Libyan Desert, r ...
, 945–715 BC, gold, Metropolitan Museum of Art Anillo de Sheshonq (46627183381).jpg, Ancient Egyptian signet ring, 664–525 BC, gold, British Museum File:Openwork dagger handle-IMG 4418-black.jpg, Ancient Chinese cast openwork dagger hilt, 6th–5th centuries BC, gold, British Museum Gold stater MET DP138743.jpg,
Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...
stater The stater (; ) was an ancient coin used in various regions of Greece. The term is also used for similar coins, imitating Greek staters, minted elsewhere in ancient Europe. History The stater, as a Greek silver currency, first as ingots, and ...
, 323–315 BC, gold, Metropolitan Museum of Art Gold funerary wreath MET DP257471.jpg,
Etruscan __NOTOC__ Etruscan may refer to: Ancient civilization *Etruscan civilization (1st millennium BC) and related things: **Etruscan language ** Etruscan architecture **Etruscan art **Etruscan cities **Etruscan coins **Etruscan history **Etruscan myt ...
funerary wreath, 4th–3rd century BC, gold, Metropolitan Museum of Art Gold aureus of Hadrian MET DP104782b.jpg,
Roman Roman or Romans most often refers to: *Rome, the capital city of Italy *Ancient Rome, Roman civilization from 8th century BC to 5th century AD *Roman people, the people of Roman civilization *Epistle to the Romans, shortened to Romans, a letter w ...
aureus The ''aureus'' ( ''aurei'', 'golden') was the main gold coin of ancient Rome from the 1st century BC to the early 4th century AD, when it was replaced by the ''solidus (coin), solidus''. This type of coin was sporadically issued during the Roman ...
of
Hadrian Hadrian ( ; ; 24 January 76 – 10 July 138) was Roman emperor from 117 to 138. Hadrian was born in Italica, close to modern Seville in Spain, an Italic peoples, Italic settlement in Hispania Baetica; his branch of the Aelia gens, Aelia '' ...
, 134–138 AD, gold, Metropolitan Museum of Art Lime Container (Poporo) MET DT1262.jpg, Quimbaya lime container, 5th–9th century, gold, Metropolitan Museum of Art File:British Museum - Room 41 (20626313758).jpg,
Anglo-Saxon The Anglo-Saxons, in some contexts simply called Saxons or the English, were a Cultural identity, cultural group who spoke Old English and inhabited much of what is now England and south-eastern Scotland in the Early Middle Ages. They traced t ...
belt buckle from
Sutton Hoo Sutton Hoo is the site of two Anglo-Saxon cemeteries dating from the 6th to 7th centuries near Woodbridge, Suffolk, England. Archaeology, Archaeologists have been excavating the area since 1938, when an undisturbed ship burial containing a wea ...
with a
niello Niello is a black mixture, usually of sulphur, copper, silver, and lead, used as an inlay on engraved or etched metal, especially silver. It is added as a powder or paste, then fired until it melts or at least softens, and flows or is push ...
interlace pattern, 7th century, gold, British Museum Byzantium, 11th century - Scyphate - 2001.25 - Cleveland Museum of Art.tif,
Byzantine The Byzantine Empire, also known as the Eastern Roman Empire, was the continuation of the Roman Empire centred on Constantinople during late antiquity and the Middle Ages. Having survived the events that caused the fall of the Western Roman E ...
scyphate Scyphate is a term frequently used in numismatics to refer to the concave or "cup-shaped" Byzantine coins of the 11th–14th centuries. This usage emerged in the premodern era and was solidified by scholars of the 19th century, when the term , a ...
, 1059–1067, gold,
Cleveland Museum of Art The Cleveland Museum of Art (CMA) is an art museum in Cleveland, Ohio, United States. Located in the Wade Park District of University Circle, the museum is internationally renowned for its substantial holdings of Asian art, Asian and Art of anc ...
,
Cleveland Cleveland is a city in the U.S. state of Ohio and the county seat of Cuyahoga County. Located along the southern shore of Lake Erie, it is situated across the Canada–U.S. maritime border and approximately west of the Ohio-Pennsylvania st ...
,
Ohio Ohio ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the ...
, USA Double Bat-Head Figure Pendant MET DT935.jpg,
Pre-Columbian In the history of the Americas, the pre-Columbian era, also known as the pre-contact era, or as the pre-Cabraline era specifically in Brazil, spans from the initial peopling of the Americas in the Upper Paleolithic to the onset of European col ...
pendant with two bat-head warriors who carry spears, 11th–16th century, gold, Metropolitan Museum of Art File:AHOTWgold lama.JPG,
Inca The Inca Empire, officially known as the Realm of the Four Parts (, ), was the largest empire in pre-Columbian America. The administrative, political, and military center of the empire was in the city of Cusco. The History of the Incas, Inca ...
hollow model of a llama, 14th-15th centuries, gold, British Museum File:The Judgement of Paris, Waddeson Bequest.jpg,
Renaissance The Renaissance ( , ) is a Periodization, period of history and a European cultural movement covering the 15th and 16th centuries. It marked the transition from the Middle Ages to modernity and was characterized by an effort to revive and sur ...
hat badge that shows the
Judgment of Paris The Judgement of Paris is a story from Greek mythology, which was one of the events that led up to the Trojan War, and in later versions to the foundation of Rome. Eris (mythology), Eris, the goddess of discord, was not invited to the wedding ...
, 16th century, enamelled gold, British Museum Box with scene depicting Roman hero Gaius Mucius Scaevola before the Etruscan king Lars Porsena MET DP170836 (cropped).jpg,
Rococo Rococo, less commonly Roccoco ( , ; or ), also known as Late Baroque, is an exceptionally ornamental and dramatic style of architecture, art and decoration which combines asymmetry, scrolling curves, gilding, white and pastel colours, sculpte ...
box, by
George Michael Moser George Michael Moser (17 January 1706 – 24 January 1783) was an artist and enameller of the 18th century, father of floral painter Mary Moser, and, with his daughter, among the founder members of the Royal Academy in 1768. Biography He ...
, 1741, gold, Metropolitan Museum of Art Jean Joseph de Saint-Germain - Candelabrum - 1946.81 - Cleveland Museum of Art.tif, Rococo candelabrum, by Jean Joseph de Saint-Germain, 1750, gilt bronze, Cleveland Museum of Art Tabatière Minerve, Mercure, Pégase (Louvre, OA 2121).jpg, Rococo snuff box with
Minerva Minerva (; ; ) is the Roman goddess of wisdom, justice, law, victory, and the sponsor of arts, trade, and strategy. She is also a goddess of warfare, though with a focus on strategic warfare, rather than the violence of gods such as Mars. Be ...
, by Jean-Malquis Lequin, 1750–1752, gold and painted enamel, Louvre File:Tabatière J-Frémin (Louvre, OA 6857).jpg,
Louis XVI style Louis XVI style, also called ''Louis Seize'', is a style of architecture, furniture, decoration and art which developed in France during the 19-year reign of Louis XVI (1774–1792), just before the French Revolution. It saw the final phase of t ...
snuff box, by Jean Frémin, 1763–1764, gold and painted enamel, Louvre File:Washstand (athénienne or lavabo) MET DP106594.jpg, Neoclassical washstand (athénienne or lavabo), 1800–1814, legs, base and shelf of yew wood, gilt bronze mounts, iron plate beneath shelf, Metropolitan Museum of Art File:Clock, French, circa 1835-1840, gilt and patinated bronze, inherited from Maurice Quentin Bauchart, 1911, inv. 17741, Museum of Decorative Arts, Paris.jpg,
Gothic Revival Gothic Revival (also referred to as Victorian Gothic or neo-Gothic) is an Architectural style, architectural movement that after a gradual build-up beginning in the second half of the 17th century became a widespread movement in the first half ...
clock, unknown French maker, 1835-1840, gilt and patinated bronze, Museum of Decorative Arts, Paris File:Teapot, by Alphonse Debain, from Paris, 1900, gilt silver and ivory, inv. 2021.63.1 MAD Paris.jpg,
Art Nouveau Art Nouveau ( ; ; ), Jugendstil and Sezessionstil in German, is an international style of art, architecture, and applied art, especially the decorative arts. It was often inspired by natural forms such as the sinuous curves of plants and ...
teapot, by Alphonse Debain, gilt silver and ivory, Museum of Decorative Arts


Etymology

''Gold'' is
cognate In historical linguistics, cognates or lexical cognates are sets of words that have been inherited in direct descent from an etymological ancestor in a common parent language. Because language change can have radical effects on both the s ...
with similar words in many
Germanic languages The Germanic languages are a branch of the Indo-European languages, Indo-European language family spoken natively by a population of about 515 million people mainly in Europe, North America, Oceania, and Southern Africa. The most widely spoke ...
, deriving via
Proto-Germanic Proto-Germanic (abbreviated PGmc; also called Common Germanic) is the linguistic reconstruction, reconstructed proto-language of the Germanic languages, Germanic branch of the Indo-European languages. Proto-Germanic eventually developed from ...
*''gulþą'' from
Proto-Indo-European Proto-Indo-European (PIE) is the reconstructed common ancestor of the Indo-European language family. No direct record of Proto-Indo-European exists; its proposed features have been derived by linguistic reconstruction from documented Indo-Euro ...
*''ǵʰelh₃-'' . The symbol ''Au'' is from the
Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...
. The Proto-Indo-European ancestor of ''aurum'' was ''*h₂é-h₂us-o-'', meaning . This word is derived from the same
root In vascular plants, the roots are the plant organ, organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often bel ...
(Proto-Indo-European ''*h₂u̯es-'' ) as ''*h₂éu̯sōs'', the ancestor of the Latin word . This etymological relationship is presumably behind the frequent claim in scientific publications that meant .Christie, A and Brathwaite, R. (Last updated 2 November 2011
Mineral Commodity Report 14 — Gold
Institute of geological and Nuclear sciences Ltd – Retrieved 7 June 2012


Culture

In popular culture gold is a high standard of excellence, often used in awards. Great achievements are frequently rewarded with gold, in the form of
gold medal A gold medal is a medal awarded for highest achievement in a non-military field. Its name derives from the use of at least a fraction of gold in form of plating or alloying in its manufacture. Since the eighteenth century, gold medals have b ...
s, gold
trophies A trophy is a tangible, decorative item used to remind of a specific achievement, serving as recognition or evidence of merit. Trophies are most commonly awarded for sporting events, ranging from youth sports to professional level athletics. Add ...
and other decorations. Winners of athletic events and other graded competitions are usually awarded a gold medal. Many awards such as the
Nobel Prize The Nobel Prizes ( ; ; ) are awards administered by the Nobel Foundation and granted in accordance with the principle of "for the greatest benefit to humankind". The prizes were first awarded in 1901, marking the fifth anniversary of Alfred N ...
are made from gold as well. Other award statues and prizes are depicted in gold or are gold plated (such as the
Academy Awards The Academy Awards, commonly known as the Oscars, are awards for artistic and technical merit in film. They are presented annually by the Academy of Motion Picture Arts and Sciences (AMPAS) in the United States in recognition of excellence in ...
, the
Golden Globe Awards The Golden Globe Awards are awards presented for excellence in both international film and television. It is an annual Awards ceremony, award ceremony held since 1944 to honor artists and professionals and their work. The ceremony is normally ...
, the
Emmy Awards The Emmy Awards, or Emmys, are an extensive range of awards for artistic and technical merit for the television industry. A number of annual Emmy Award ceremonies are held throughout the year, each with their own set of rules and award categor ...
, the
Palme d'Or The (; ) is the highest prize awarded to the director of the Best Feature Film of the Official Competition at the Cannes Film Festival. It was introduced in 1955 by the festival's organizing committee. Previously, from 1939 to 1954, the festiv ...
, and the
British Academy Film Awards The British Academy Film Awards, more commonly known as the BAFTAs or BAFTA Awards, is an annual film award show hosted by the British Academy of Film and Television Arts (BAFTA) to honour the best British and international contributions to f ...
).
Aristotle Aristotle (; 384–322 BC) was an Ancient Greek philosophy, Ancient Greek philosopher and polymath. His writings cover a broad range of subjects spanning the natural sciences, philosophy, linguistics, economics, politics, psychology, a ...
in his
ethics Ethics is the philosophy, philosophical study of Morality, moral phenomena. Also called moral philosophy, it investigates Normativity, normative questions about what people ought to do or which behavior is morally right. Its main branches inclu ...
used gold symbolism when referring to what is now known as the golden mean. Similarly, gold is associated with perfect or divine principles, such as in the case of the
golden ratio In mathematics, two quantities are in the golden ratio if their ratio is the same as the ratio of their summation, sum to the larger of the two quantities. Expressed algebraically, for quantities and with , is in a golden ratio to if \fr ...
and the
Golden Rule The Golden Rule is the principle of treating others as one would want to be treated by them. It is sometimes called an ethics of reciprocity, meaning that one should reciprocate to others how one would like them to treat the person (not neces ...
. Gold is further associated with the wisdom of aging and fruition. The fiftieth
wedding anniversary A wedding anniversary is the anniversary of the date that a wedding took place. Couples often mark the occasion by celebrating their relationship, either privately or with a larger party. Special celebrations and gifts are often given for partic ...
is golden. A person's most valued or most successful latter years are sometimes considered "golden years" or "golden jubilee". The height of a civilization is referred to as a
golden age The term Golden Age comes from Greek mythology, particularly the ''Works and Days'' of Hesiod, and is part of the description of temporal decline of the state of peoples through five Ages of Man, Ages, Gold being the first and the one during wh ...
.


Religion

The first known prehistoric human usages of gold were
religious Religion is a range of social- cultural systems, including designated behaviors and practices, morals, beliefs, worldviews, texts, sanctified places, prophecies, ethics, or organizations, that generally relate humanity to supernatural ...
in nature. In some forms of Christianity and Judaism, gold has been associated both with the sacred and evil. In the
Book of Exodus The Book of Exodus (from ; ''Šəmōṯ'', 'Names'; ) is the second book of the Bible. It is the first part of the narrative of the Exodus, the origin myth of the Israelites, in which they leave slavery in Biblical Egypt through the strength of ...
, the
Golden Calf According to the Torah, the Bible, and the Quran, the golden calf () was a cult image made by the Israelites when Moses went up to Mount Sinai (bible), Mount Sinai. In Hebrew, the incident is known as "the sin of the calf" (). It is first mentio ...
is a symbol of
idolatry Idolatry is the worship of an idol as though it were a deity. In Abrahamic religions (namely Judaism, Samaritanism, Christianity, Islam, and the Baháʼí Faith) idolatry connotes the worship of something or someone other than the Abrahamic ...
, while in the
Book of Genesis The Book of Genesis (from Greek language, Greek ; ; ) is the first book of the Hebrew Bible and the Christian Old Testament. Its Hebrew name is the same as its incipit, first word, (In the beginning (phrase), 'In the beginning'). Genesis purpor ...
,
Abraham Abraham (originally Abram) is the common Hebrews, Hebrew Patriarchs (Bible), patriarch of the Abrahamic religions, including Judaism, Christianity, and Islam. In Judaism, he is the founding father who began the Covenant (biblical), covenanta ...
was said to be rich in gold and silver, and Moses was instructed to cover the
Mercy Seat According to the Hebrew Bible, the ''kaporet'' ( ''kapōreṯ'') or mercy seat was the gold lid placed on the Ark of the Covenant, with two cherubim at the ends to cover and create the space in which Yahweh appeared and dwelled. This was connecte ...
of the Ark of the Covenant with pure gold. In
Byzantine The Byzantine Empire, also known as the Eastern Roman Empire, was the continuation of the Roman Empire centred on Constantinople during late antiquity and the Middle Ages. Having survived the events that caused the fall of the Western Roman E ...
icon An icon () is a religious work of art, most commonly a painting, in the cultures of the Eastern Orthodox, Oriental Orthodox, Catholic Church, Catholic, and Lutheranism, Lutheran churches. The most common subjects include Jesus, Mary, mother of ...
ography the halos of Christ,
Virgin Mary Mary was a first-century Jewish woman of Nazareth, the wife of Saint Joseph, Joseph and the mother of Jesus. She is an important figure of Christianity, venerated under titles of Mary, mother of Jesus, various titles such as Perpetual virginity ...
and the saints are often golden. In
Islam Islam is an Abrahamic religions, Abrahamic monotheistic religion based on the Quran, and the teachings of Muhammad. Adherents of Islam are called Muslims, who are estimated to number Islam by country, 2 billion worldwide and are the world ...
, gold (along with
silk Silk is a natural fiber, natural protein fiber, some forms of which can be weaving, woven into textiles. The protein fiber of silk is composed mainly of fibroin and is most commonly produced by certain insect larvae to form cocoon (silk), c ...
) is often cited as being forbidden for men to wear. Abu Bakr al-Jazaeri, quoting a
hadith Hadith is the Arabic word for a 'report' or an 'account f an event and refers to the Islamic oral tradition of anecdotes containing the purported words, actions, and the silent approvals of the Islamic prophet Muhammad or his immediate circle ...
, said that " e wearing of silk and gold are forbidden on the males of my nation, and they are lawful to their women". This, however, has not been enforced consistently throughout history, e.g. in the Ottoman Empire. Further, small gold accents on clothing, such as in
embroidery Embroidery is the art of decorating Textile, fabric or other materials using a Sewing needle, needle to stitch Yarn, thread or yarn. It is one of the oldest forms of Textile arts, textile art, with origins dating back thousands of years across ...
, may be permitted. In
ancient Greek religion Religious practices in ancient Greece encompassed a collection of beliefs, rituals, and Greek mythology, mythology, in the form of both popular public religion and Cult (religious practice), cult practices. The application of the modern concept ...
and
mythology Myth is a genre of folklore consisting primarily of narratives that play a fundamental role in a society. For scholars, this is very different from the vernacular usage of the term "myth" that refers to a belief that is not true. Instead, the ...
,
Theia Theia (; , also rendered Thea or Thia), also called Euryphaessa (, "wide-shining"), is one of the twelve Titans, the children of the earth goddess Gaia and the sky god Uranus in Greek mythology. She is the Greek goddess of sight and vision, an ...
was seen as the goddess of gold, silver and other
gemstone A gemstone (also called a fine gem, jewel, precious stone, semiprecious stone, or simply gem) is a piece of mineral crystal which, when cut or polished, is used to make jewellery, jewelry or other adornments. Certain Rock (geology), rocks (such ...
s. According to
Christopher Columbus Christopher Columbus (; between 25 August and 31 October 1451 – 20 May 1506) was an Italians, Italian explorer and navigator from the Republic of Genoa who completed Voyages of Christopher Columbus, four Spanish-based voyages across the At ...
, those who had something of gold were in possession of something of great value on Earth and a substance to even help souls to paradise.
Wedding ring A wedding ring or wedding band is a finger ring that indicates that its wearer is married. It is usually forged from metal, traditionally gold or another precious metal. Rings were used in ancient Rome during marriage. In western culture, a ...
s are typically made of gold. It is long lasting and unaffected by the passage of time and may aid in the ring symbolism of eternal vows before God and the perfection the marriage signifies. In Orthodox Christian wedding ceremonies, the wedded couple is adorned with a golden crown (though some opt for wreaths, instead) during the ceremony, an amalgamation of symbolic rites. On 24 August 2020,
Israel Israel, officially the State of Israel, is a country in West Asia. It Borders of Israel, shares borders with Lebanon to the north, Syria to the north-east, Jordan to the east, Egypt to the south-west, and the Mediterranean Sea to the west. Isr ...
i archaeologists discovered a trove of early
Islam Islam is an Abrahamic religions, Abrahamic monotheistic religion based on the Quran, and the teachings of Muhammad. Adherents of Islam are called Muslims, who are estimated to number Islam by country, 2 billion worldwide and are the world ...
ic gold coins near the central city of
Yavne Yavne () is a city in the Central District (Israel), Central District of Israel. In 2022, it had a population of 56,232. Modern Yavne was established in 1949. It is located near the ruins of the ancient town of Yibna (known also as Jamnia and Jab ...
. Analysis of the extremely rare collection of 425 gold coins indicated that they were from the late 9th century. Dating to around 1,100 years back, the gold coins were from the
Abbasid Caliphate The Abbasid Caliphate or Abbasid Empire (; ) was the third caliphate to succeed the Islamic prophet Muhammad. It was founded by a dynasty descended from Muhammad's uncle, Abbas ibn Abd al-Muttalib (566–653 CE), from whom the dynasty takes ...
.


Production

According to the
United States Geological Survey The United States Geological Survey (USGS), founded as the Geological Survey, is an agency of the U.S. Department of the Interior whose work spans the disciplines of biology, geography, geology, and hydrology. The agency was founded on Mar ...
in 2016, about of gold has been accounted for, of which 85% remains in active use.


Mining and prospecting

Since the 1880s, South Africa has been the source of a large proportion of the world's gold supply, and about 22% of the gold presently accounted is from South Africa. Production in 1970 accounted for 79% of the world supply, about 1,480 tonnes. In 2007 China (with 276 tonnes) overtook South Africa as the world's largest gold producer, the first time since 1905 that South Africa had not been the largest. In 2023,
China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...
was the world's leading gold-mining country, followed in order by Russia, Australia, Canada, the United States and Ghana. In South America, the controversial project Pascua Lama aims at exploitation of rich fields in the high mountains of
Atacama Desert The Atacama Desert () is a desert plateau located on the Pacific Ocean, Pacific coast of South America, in the north of Chile. Stretching over a strip of land west of the Andes Mountains, it covers an area of , which increases to if the barre ...
, at the border between
Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...
and
Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...
. It has been estimated that up to one-quarter of the yearly global gold production originates from artisanal or small scale mining. The city of
Johannesburg Johannesburg ( , , ; Zulu language, Zulu and Xhosa language, Xhosa: eGoli ) (colloquially known as Jozi, Joburg, Jo'burg or "The City of Gold") is the most populous city in South Africa. With 5,538,596 people in the City of Johannesburg alon ...
located in South Africa was founded as a result of the
Witwatersrand Gold Rush The Witwatersrand Gold Rush was a gold rush that began in 1886 and led to the establishment of Johannesburg, South Africa. It was a part of the Mineral Revolution. Origins In the modern-day province of Mpumalanga, gold miners in the alluvial ...
which resulted in the discovery of some of the largest natural gold deposits in recorded history. The gold fields are confined to the northern and north-western edges of the
Witwatersrand basin The Witwatersrand (, ; ; locally the Rand or, less commonly, the Reef) is a , north-facing scarp in South Africa. It consists of a hard, erosion-resistant quartzite metamorphic rock, over which several north-flowing rivers form waterfalls, wh ...
, which is a thick layer of
archean The Archean ( , also spelled Archaean or Archæan), in older sources sometimes called the Archaeozoic, is the second of the four geologic eons of Earth's history of Earth, history, preceded by the Hadean Eon and followed by the Proterozoic and t ...
rocks located, in most places, deep under the Free State,
Gauteng Gauteng ( , ; Sotho-Tswana languages, Sotho-Tswana for 'place of gold'; or ) is one of the nine provinces of South Africa. Situated on the Highveld, Gauteng is the smallest province by land area in South Africa. Although Gauteng accounts f ...
and surrounding provinces.Truswell, J.F. (1977). ''The Geological Evolution of South Africa''. pp. 21–28. Purnell, Cape Town. These Witwatersrand rocks are exposed at the surface on the
Witwatersrand The Witwatersrand (, ; ; locally the Rand or, less commonly, the Reef) is a , north-facing scarp in South Africa. It consists of a hard, erosion-resistant quartzite metamorphic rock, over which several north-flowing rivers form waterfalls, w ...
, in and around Johannesburg, but also in isolated patches to the south-east and south-west of Johannesburg, as well as in an arc around the
Vredefort Dome The Vredefort impact structure is one of the largest impact structures on Earth. The crater, which has since been eroded away, has been estimated at across when it was formed, the latter estimate suggesting the initial crater was larger than ...
which lies close to the center of the Witwatersrand basin. From these surface exposures the basin dips extensively, requiring some of the mining to occur at depths of nearly , making them, especially the
Savuka Savuka, occasionally referred to as Johnny Clegg & Savuka, was a multi-racial South African band formed in 1986 by Johnny Clegg after the disbanding of Juluka. Savuka's music blended traditional Zulu music, Zulu musical influences with Celtic m ...
and TauTona mines to the south-west of Johannesburg, the deepest mines on Earth. The gold is found only in six areas where
archean The Archean ( , also spelled Archaean or Archæan), in older sources sometimes called the Archaeozoic, is the second of the four geologic eons of Earth's history of Earth, history, preceded by the Hadean Eon and followed by the Proterozoic and t ...
rivers from the north and north-west formed extensive pebbly
Braided river A braided river (also called braided channel or braided stream) consists of a network of river channel (geography), channels separated by small, often temporary, islands called ''braid bars'' or, in British English usage, ''aits'' or ''eyots''. ...
deltas before draining into the "Witwatersrand sea" where the rest of the Witwatersrand sediments were deposited. The
Second Boer War The Second Boer War (, , 11 October 189931 May 1902), also known as the Boer War, Transvaal War, Anglo–Boer War, or South African War, was a conflict fought between the British Empire and the two Boer republics (the South African Republic and ...
of 1899–1901 between the
British Empire The British Empire comprised the dominions, Crown colony, colonies, protectorates, League of Nations mandate, mandates, and other Dependent territory, territories ruled or administered by the United Kingdom and its predecessor states. It bega ...
and the
Afrikaner Afrikaners () are a Southern African ethnic group descended from predominantly Dutch settlers who first arrived at the Cape of Good Hope in 1652.Entry: Cape Colony. ''Encyclopædia Britannica Volume 4 Part 2: Brain to Casting''. Encyclopæd ...
Boer Boers ( ; ; ) are the descendants of the proto Afrikaans-speaking Free Burghers of the eastern Cape frontier in Southern Africa during the 17th, 18th, and 19th centuries. From 1652 to 1795, the Dutch East India Company controlled the Dutch ...
s was at least partly over the rights of miners and possession of the gold wealth in South Africa. During the 19th century,
gold rush A gold rush or gold fever is a discovery of gold—sometimes accompanied by other precious metals and rare-earth minerals—that brings an onrush of miners seeking their fortune. Major gold rushes took place in the 19th century in Australia, ...
es occurred whenever large gold deposits were discovered. The first documented discovery of gold in the United States was at the Reed Gold Mine near Georgeville, North Carolina in 1803. The first major gold strike in the United States occurred in a small north Georgia town called Dahlonega. Further gold rushes occurred in
California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
,
Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...
, the
Black Hills The Black Hills is an isolated mountain range rising from the Great Plains of North America in western South Dakota and extending into Wyoming, United States. Black Elk Peak, which rises to , is the range's highest summit. The name of the range ...
,
Otago Otago (, ; ) is a regions of New Zealand, region of New Zealand located in the southern half of the South Island and administered by the Otago Regional Council. It has an area of approximately , making it the country's second largest local go ...
in New Zealand, a number of locations across
Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
,
Witwatersrand The Witwatersrand (, ; ; locally the Rand or, less commonly, the Reef) is a , north-facing scarp in South Africa. It consists of a hard, erosion-resistant quartzite metamorphic rock, over which several north-flowing rivers form waterfalls, w ...
in South Africa, and the Klondike in Canada. Grasberg mine located in Papua,
Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...
is the largest
gold mine Gold mining is the extraction of gold by mining. Historically, mining gold from alluvial deposits used manual separation processes, such as gold panning. The expansion of gold mining to ores that are not on the surface has led to more comple ...
in the world.


Extraction and refining

Gold extraction Gold extraction is the extraction of gold from dilute ores using a combination of chemical processes. Gold mining produces about 3600 tons annually, and another 300 tons is produced from recycling. Since the 20th century, gold has been principal ...
is most economical in large, easily mined deposits. Ore grades as little as 0.5 parts per million (ppm) can be economical. Typical ore grades in
open-pit Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, is a surface mining technique that extracts rock (geology), rock or minerals from the earth. Open-pit mines are used when deposits of commercially ...
mines are 1–5 ppm; ore grades in underground or
hard rock Hard rock or heavy rock is a heavier subgenre of rock music typified by aggressive vocals and Distortion (music), distorted electric guitars. Hard rock began in the mid-1960s with the Garage rock, garage, Psychedelic rock, psychedelic and blues ...
mines are usually at least 3 ppm. Because ore grades of 30 ppm are usually needed before gold is visible to the naked eye, in most gold mines the gold is invisible. The average gold mining and extraction costs were about $317 per troy ounce in 2007, but these can vary widely depending on mining type and ore quality; global mine production amounted to 2,471.1 tonnes. After initial production, gold is often subsequently refined industrially by the Wohlwill process which is based on
electrolysis In chemistry and manufacturing, electrolysis is a technique that uses Direct current, direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of c ...
or by the Miller process, that is chlorination in the melt. The Wohlwill process results in higher purity, but is more complex and is only applied in small-scale installations. Other methods of assaying and purifying smaller amounts of gold include parting and inquartation as well as
cupellation Cupellation is a refining process in metallurgy in which ores or alloyed metals are treated under very high temperatures and subjected to controlled operations to separate noble metals, like gold and silver, from base metals, like lead, co ...
, or refining methods based on the dissolution of gold in aqua regia.


Recycling

In 1997, recycled gold accounted for approximately 20% of the 2700 tons of gold supplied to the market. Jewelry companies such as Generation Collection and computer companies including
Dell Dell Inc. is an American technology company that develops, sells, repairs, and supports personal computers (PCs), Server (computing), servers, data storage devices, network switches, software, computer peripherals including printers and webcam ...
conduct recycling. As of 2020, the amount of
carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...
produced in mining a kilogram of gold is 16 tonnes, while recycling a kilogram of gold produces 53 kilograms of equivalent. Approximately 30 percent of the global gold supply is recycled and not mined as of 2020.


Consumption

The consumption of gold produced in the world is about 50% in jewelry, 40% in investments, and 10% in industry. According to the
World Gold Council The World Gold Council is an international trade association for the gold industry. It is headquartered in London and has offices in India, China, Singapore, the UAE and the United States. The organization's members are gold mining companies. ...
, China was the world's largest single consumer of gold in 2013, overtaking India.


Pollution

Gold production is associated with contribution to hazardous
pollution Pollution is the introduction of contaminants into the natural environment that cause harm. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the component ...
. Low-grade gold ore may contain less than one ppm gold metal; such ore is ground and mixed with
sodium cyanide Sodium cyanide is a compound with the formula Na C N and the structure . It is a white, water-soluble solid. Cyanide has a high affinity for metals, which leads to the high toxicity of this salt. Its main application, in gold mining, also expl ...
to dissolve the gold. Cyanide is a highly poisonous chemical, which can kill living creatures when exposed in minute quantities. Many cyanide spills from gold mines have occurred in both developed and developing countries which killed aquatic life in long stretches of affected rivers. Environmentalists consider these events major environmental disasters. Up to thirty tons of used ore can be dumped as waste for producing one troy ounce of gold.Behind gold's glitter, torn lands and pointed questions
, ''The New York Times'', 24 October 2005
Gold ore dumps are the source of many heavy elements such as cadmium, lead, zinc, copper,
arsenic Arsenic is a chemical element; it has Symbol (chemistry), symbol As and atomic number 33. It is a metalloid and one of the pnictogens, and therefore shares many properties with its group 15 neighbors phosphorus and antimony. Arsenic is not ...
,
selenium Selenium is a chemical element; it has symbol (chemistry), symbol Se and atomic number 34. It has various physical appearances, including a brick-red powder, a vitreous black solid, and a grey metallic-looking form. It seldom occurs in this elem ...
and mercury. When sulfide-bearing minerals in these ore dumps are exposed to air and water, the sulfide transforms into
sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...
which in turn dissolves these heavy metals facilitating their passage into surface water and ground water. This process is called
acid mine drainage Acid mine drainage, acid and metalliferous drainage (AMD), or acid rock drainage (ARD) is the outflow of acidic water from metal mines and coal mines. Acid rock drainage occurs naturally within some environments as part of the rock weatherin ...
. These gold ore dumps contain long-term, highly
hazardous waste Hazardous waste is waste that must be handled properly to avoid damaging human health or the environment. Waste can be hazardous because it is Toxicity, toxic, Chemical reaction, reacts violently with other chemicals, or is Corrosion, corrosive, ...
. It was once common to use mercury to recover gold from ore, but today the use of mercury is largely limited to small-scale individual miners. Minute quantities of mercury compounds can reach water bodies, causing heavy metal contamination. Mercury can then enter into the human food chain in the form of
methylmercury Methylmercury is an organometallic cation with the formula . It is the simplest organomercury compound. Methylmercury is extremely toxic, and its derivatives are the major source of organic mercury for humans. It is a bioaccumulative environment ...
.
Mercury poisoning Mercury poisoning is a type of metal poisoning due to exposure to mercury. Symptoms depend upon the type, dose, method, and duration of exposure. They may include muscle weakness, poor coordination, numbness in the hands and feet, skin rashe ...
in humans can cause severe brain damage. Gold extraction is also a highly energy-intensive industry, extracting ore from deep mines and grinding the large quantity of ore for further chemical extraction requires nearly 25 kWh of electricity per gram of gold produced.


Monetary use

Gold has been widely used throughout the world as
money Money is any item or verifiable record that is generally accepted as payment for goods and services and repayment of debts, such as taxes, in a particular country or socio-economic context. The primary functions which distinguish money are: m ...
, for efficient indirect exchange (versus
barter In trade, barter (derived from ''bareter'') is a system of exchange (economics), exchange in which participants in a financial transaction, transaction directly exchange good (economics), goods or service (economics), services for other goods ...
), and to store wealth in
hoard A hoard or "wealth deposit" is an archaeological term for a collection of valuable objects or artifacts, sometimes purposely buried in the ground, in which case it is sometimes also known as a cache. This would usually be with the intention of ...
s. For exchange purposes,
mints A mint or breath mint is a food item often consumed as an after-meal refreshment or before business and social engagements to improve breath odor. Mints are commonly believed to soothe the stomach, given their association with natural byproducts ...
produce standardized
gold bullion A gold bar, also known as gold bullion or a gold ingot, is a quantity of refining, refined metallic gold that can be shaped in various forms, produced under standardized conditions of manufacture, labeling, and record-keeping. Larger varietie ...
coins A coin is a small object, usually round and flat, used primarily as a medium of exchange or legal tender. They are standardized in weight, and produced in large quantities at a mint in order to facilitate trade. They are most often issued by ...
, bars and other units of fixed weight and purity. The first known coins containing gold were struck in Lydia, Asia Minor, around 600 BC. The '' talent'' coin of gold in use during the periods of Grecian history both before and during the time of the life of Homer weighed between 8.42 and 8.75 grams. From an earlier preference in using silver, European economies re-established the minting of gold as coinage during the thirteenth and fourteenth centuries. Bills (that mature into gold coin) and gold certificates (convertible into gold coin at the issuing bank) added to the circulating stock of
gold standard A gold standard is a backed currency, monetary system in which the standard economics, economic unit of account is based on a fixed quantity of gold. The gold standard was the basis for the international monetary system from the 1870s to the ...
money in most 19th century industrial economies. In preparation for
World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...
the warring nations moved to fractional gold standards, inflating their currencies to finance the war effort. Post-war, the victorious countries, most notably Britain, gradually restored gold-convertibility, but international flows of gold via bills of exchange remained embargoed; international shipments were made exclusively for bilateral trades or to pay war reparations. After
World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
gold was replaced by a system of nominally convertible currencies related by fixed exchange rates following the
Bretton Woods system The Bretton Woods system of monetary management established the rules for commercial relations among 44 countries, including the United States, Canada, Western European countries, and Australia, after the 1944 Bretton Woods Agreement until the ...
.
Gold standard A gold standard is a backed currency, monetary system in which the standard economics, economic unit of account is based on a fixed quantity of gold. The gold standard was the basis for the international monetary system from the 1870s to the ...
s and the direct convertibility of currencies to gold have been abandoned by world governments, led in 1971 by the United States' refusal to redeem its dollars in gold.
Fiat currency Fiat money is a type of government-issued currency that is not backed by a precious metal, such as gold or silver, nor by any other tangible asset or commodity. Fiat currency is typically designated by the issuing government to be legal tender, ...
now fills most monetary roles.
Switzerland Switzerland, officially the Swiss Confederation, is a landlocked country located in west-central Europe. It is bordered by Italy to the south, France to the west, Germany to the north, and Austria and Liechtenstein to the east. Switzerland ...
was the last country to tie its currency to gold; this was ended by a referendum in 1999. Central banks continue to keep a portion of their liquid reserves as gold in some form, and metals exchanges such as the
London Bullion Market Association The London Bullion Market Association (now known simply as LBMA), established in 1987, is the international trade association representing the global Over The Counter (OTC) bullion market, and defines itself as "the global authority on precious ...
still clear transactions denominated in gold, including future delivery contracts. Today,
gold mining Gold mining is the extraction of gold by mining. Historically, mining gold from Alluvium, alluvial deposits used manual separation processes, such as gold panning. The expansion of gold mining to ores that are not on the surface has led to mor ...
output is declining. With the sharp growth of economies in the 20th century, and increasing foreign exchange, the world's
gold reserve A gold reserve is the gold held by a national central bank, intended mainly as a guarantee to redeem promises to pay depositors, note holders (e.g. paper money), or trading peers, during the eras of the gold standard, and also as a store of v ...
s and their trading market have become a small fraction of all markets and fixed exchange rates of currencies to gold have been replaced by floating prices for gold and gold
future contract In finance, a futures contract (sometimes called futures) is a standardized legal contract to buy or sell something at a predetermined price for delivery at a specified time in the future, between parties not yet known to each other. The item tr ...
. Though the gold stock grows by only 1% or 2% per year, very little metal is irretrievably consumed. Inventory above ground would satisfy many decades of industrial and even artisan uses at current prices. The gold proportion (
fineness The fineness of a precious metal object (coin, bar, jewelry, etc.) represents the weight of ''fine metal'' therein, in proportion to the total weight which includes alloying base metals and any impurities. Alloy metals are added to increase hard ...
) of alloys is measured by
karat The fineness of a precious metal object (coin, bar, jewelry, etc.) represents the weight of ''fine metal'' therein, in proportion to the total weight which includes alloying base metals and any impurities. Alloy metals are added to increase hardn ...
(k). Pure gold (commercially termed ''fine'' gold) is designated as 24 karat, abbreviated 24k. English gold coins intended for circulation from 1526 into the 1930s were typically a standard 22k alloy called
crown gold Crown gold is a 22 karat (kt) gold alloy used in the crown coin introduced in England in 1526 (by Henry VIII). In this alloy, the proportion of gold is 22 parts out of 24 (91.667% gold). Crown gold is appreciably less prone to wear than the sof ...
, for hardness (American gold coins for circulation after 1837 contain an alloy of 0.900 fine gold, or 21.6 kt). Often the prices of various
platinum Platinum is a chemical element; it has Symbol (chemistry), symbol Pt and atomic number 78. It is a density, dense, malleable, ductility, ductile, highly unreactive, precious metal, precious, silverish-white transition metal. Its name origina ...
group metals can be much higher than gold. Though gold has been used as a standard for
currencies A currency is a standardization of money in any form, in use or currency in circulation, circulation as a medium of exchange, for example banknotes and coins. A more general definition is that a currency is a ''system of money'' in common use wi ...
to a greater degree than the platinum group metals. Gold has been used as a symbol for purity, value, royalty, and particularly roles that combine these properties. Gold as a sign of wealth and prestige was ridiculed by
Thomas More Sir Thomas More (7 February 1478 – 6 July 1535), venerated in the Catholic Church as Saint Thomas More, was an English lawyer, judge, social philosopher, author, statesman, theologian, and noted Renaissance humanist. He also served Henry VII ...
in his treatise ''
Utopia A utopia ( ) typically describes an imagined community or society that possesses highly desirable or near-perfect qualities for its members. It was coined by Sir Thomas More for his 1516 book ''Utopia (book), Utopia'', which describes a fictiona ...
''. On that imaginary island, gold is so abundant that it is used to make chains for slaves, tableware, and lavatory seats. When ambassadors from other countries arrive, dressed in ostentatious gold jewels and badges, the Utopians mistake them for menial servants, paying homage instead to the most modestly dressed of their party. The
ISO 4217 ISO 4217 is a standard published by the International Organization for Standardization (ISO) that defines alpha codes and numeric codes for the representation of currencies and provides information about the relationships between individ ...
currency code of gold is XAU. Many holders of gold store it in form of
bullion Bullion is non-ferrous metal that has been refined to a high standard of elemental purity. The term is ordinarily applied to bulk metal used in the production of coins and especially to precious metals such as gold and silver. It comes from ...
coins or bars as a hedge against
inflation In economics, inflation is an increase in the average price of goods and services in terms of money. This increase is measured using a price index, typically a consumer price index (CPI). When the general price level rises, each unit of curre ...
or other economic disruptions, though its efficacy as such has been questioned; historically, it has not proven itself reliable as a hedging instrument. Modern
bullion coin A bullion coin (also known as a specie) is a coin struck from highly refined precious metal (bullion) and kept as a store of value or an investment rather than used in day-to-day commerce, or collectable, with numismatic value beyond that of its ...
s for investment or collector purposes do not require good mechanical wear properties; they are typically fine gold at 24k, although the
American Gold Eagle The American Gold Eagle is an official gold bullion coin of the United States. Authorized under the Gold Bullion Coin Act of 1985, it was first released by the United States Mint in 1986. Because the term "eagle" also is the official United St ...
and the British
gold sovereign The sovereign is a British gold coin with a nominal value of one pound sterling (£1) and contains of pure gold. Struck since 1817, it was originally a circulating coin that was accepted in Britain and elsewhere in the world; it is now a ...
continue to be minted in 22k (0.92) metal in historical tradition, and the South African
Krugerrand The Krugerrand (; ) is a South African coin, first minted on 3 July 1967 to help market South African gold and produced by Rand Refinery and the South African Mint. The name is a compound of '' Paul Kruger'', the former President of the South ...
, first released in 1967, is also 22k (0.92). The ''special issue''
Canadian Gold Maple Leaf The Canadian Gold Maple Leaf (GML; ) is a gold coin, gold bullion coin that is issued annually by the Government of Canada. It is produced by the Royal Canadian Mint. The Gold Maple Leaf is legal tender with a face value of 50 Canadian dollars. ...
coin contains the highest purity gold of any
bullion coin A bullion coin (also known as a specie) is a coin struck from highly refined precious metal (bullion) and kept as a store of value or an investment rather than used in day-to-day commerce, or collectable, with numismatic value beyond that of its ...
, at 99.999% or 0.99999, while the ''popular issue'' Canadian Gold Maple Leaf coin has a purity of 99.99%. In 2006, the
United States Mint The United States Mint is a bureau of the United States Department of the Treasury, Department of the Treasury responsible for producing coinage for the United States to conduct its trade and commerce, as well as controlling the movement of bull ...
began producing the American Buffalo gold bullion coin with a purity of 99.99%. The
Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
n Gold Kangaroos were first coined in 1986 as the
Australian Gold Nugget The Australian Gold Nugget, also sometimes known as the Australian Gold Kangaroo, is a gold bullion coin minted by the Perth Mint. The coins have been minted in denominations of oz, oz, oz, oz, 1 oz, 2 oz, 10 oz, and 1 kg of 24 car ...
but changed the reverse design in 1989. Other modern coins include the
Austria Austria, formally the Republic of Austria, is a landlocked country in Central Europe, lying in the Eastern Alps. It is a federation of nine Federal states of Austria, states, of which the capital Vienna is the List of largest cities in Aust ...
n
Vienna Philharmonic Vienna Philharmonic (VPO; ) is an orchestra that was founded in 1842 and is considered to be one of the finest in the world. The Vienna Philharmonic is based at the Musikverein in Vienna, Austria. Its members are selected from the orchestra of ...
bullion coin and the
Chinese Gold Panda The Chinese Gold Panda () is a series of gold bullion coins issued by the People's Republic of China. The Official Mint of the People's Republic of China introduced the panda gold bullion coins in 1982. The panda design changes every year (with ...
.


Price

Like other precious metals, gold is measured by
troy weight Troy weight is a system of units of mass that originated in the Kingdom of England in the 15th century and is primarily used in the precious metals industry. The troy weight units are the grain, the pennyweight (24 grains), the troy ounce (20 ...
and by grams. The proportion of gold in the alloy is measured by ''
karat The fineness of a precious metal object (coin, bar, jewelry, etc.) represents the weight of ''fine metal'' therein, in proportion to the total weight which includes alloying base metals and any impurities. Alloy metals are added to increase hardn ...
'' (k), with 24 karat (24k) being pure gold (100%), and lower karat numbers proportionally less (18k = 75%). The purity of a
gold bar A gold bar, also known as gold bullion or a gold ingot, is a quantity of refined metallic gold that can be shaped in various forms, produced under standardized conditions of manufacture, labeling, and record-keeping. Larger varieties of gold ...
or coin can also be expressed as a decimal figure ranging from 0 to 1, known as the
millesimal fineness The fineness of a precious metal object (coin, bar, jewelry, etc.) represents the weight of ''fine metal'' therein, in proportion to the total weight which includes alloying base metals and any impurities. Alloy metals are added to increase hard ...
, such as 0.995 being nearly pure. The price of gold is determined through trading in the gold and derivatives markets, but a procedure known as the
Gold Fixing The London Gold Fixing (or Gold Fix) is the setting of the price of gold that takes place via a dedicated conference line. It was formerly held on the London premises of Nathan Mayer Rothschild & Sons by the members of The London Gold Market Fixi ...
in
London London is the Capital city, capital and List of urban areas in the United Kingdom, largest city of both England and the United Kingdom, with a population of in . London metropolitan area, Its wider metropolitan area is the largest in Wester ...
, originating in September 1919, provides a daily benchmark price to the industry. The afternoon fixing was introduced in 1968 to provide a price when US markets are open. , gold was valued at around $106 per gram ($3,300 per troy ounce).


History

Historically gold coinage was widely used as currency; when
paper money Paper money, often referred to as a note or a bill (North American English), is a type of negotiable promissory note that is payable to the bearer on demand, making it a form of currency. The main types of paper money are government notes, which ...
was introduced, it typically was a
receipt A receipt (also known as a packing list, packing slip, packaging slip, (delivery) docket, shipping list, delivery list, bill of the parcel, Manifest (transportation), manifest, or customer receipt) is a document acknowledging that something h ...
redeemable for gold coin or
bullion Bullion is non-ferrous metal that has been refined to a high standard of elemental purity. The term is ordinarily applied to bulk metal used in the production of coins and especially to precious metals such as gold and silver. It comes from ...
. In a
monetary Money is any item or verifiable record that is generally accepted as payment for goods and services and repayment of debts, such as taxes, in a particular country or socio-economic context. The primary functions which distinguish money are: med ...
system known as the
gold standard A gold standard is a backed currency, monetary system in which the standard economics, economic unit of account is based on a fixed quantity of gold. The gold standard was the basis for the international monetary system from the 1870s to the ...
, a certain
weight In science and engineering, the weight of an object is a quantity associated with the gravitational force exerted on the object by other objects in its environment, although there is some variation and debate as to the exact definition. Some sta ...
of gold was given the name of a unit of currency. For a long period, the United States government set the value of the US dollar so that one
troy ounce Troy weight is a system of units of mass that originated in the Kingdom of England in the 15th century and is primarily used in the precious metals industry. The troy weight units are the grain, the pennyweight (24 grains), the troy ounce (20 p ...
was equal to $20.67 ($0.665 per gram), but in 1934 the dollar was devalued to $35.00 per troy ounce ($0.889/g). By 1961, it was becoming hard to maintain this price, and a pool of US and European banks agreed to manipulate the market to prevent further devaluation, currency devaluation against increased gold demand. The largest gold depository in the world is that of the Federal Reserve System, U.S. Federal Reserve Bank in New York City, New York, which holds about 3% of the gold known to exist and accounted for today, as does the similarly laden United States Bullion Depository, U.S. Bullion Depository at Fort Knox. In 2005 the
World Gold Council The World Gold Council is an international trade association for the gold industry. It is headquartered in London and has offices in India, China, Singapore, the UAE and the United States. The organization's members are gold mining companies. ...
estimated total global gold supply to be 3,859 tonnes and demand to be 3,754 tonnes, giving a surplus of 105 tonnes. After 15 August 1971 Nixon shock, the price began to greatly increase, and between 1968 and 2000 the price of gold ranged widely, from a high of $850 per troy ounce ($27.33/g) on 21 January 1980, to a low of $252.90 per troy ounce ($8.13/g) on 21 June 1999 (London Gold Fixing). Prices increased rapidly from 2001, but the 1980 high was not exceeded until 3 January 2008, when a new maximum of $865.35 per troy weight, troy ounce was set. Another record price was set on 17 March 2008, at $1023.50 per troy ounce ($32.91/g). On 2 December 2009, gold reached a new high closing at $1,217.23. Gold further rallied hitting new highs in May 2010 after the European Union debt crisis prompted further purchase of gold as a safe asset. On 1 March 2011, gold hit a new all-time high of $1432.57, based on Gold as an investment, investor concerns regarding ongoing Arab Spring, unrest in North Africa as well as in the Middle East. From April 2001 to August 2011, spot gold prices more than quintupled in value against the US dollar, hitting a new all-time high of $1,913.50 on 23 August 2011, prompting speculation that the long secular bear market had ended and a bull market had returned. However, the price then began a slow decline towards $1200 per troy ounce in late 2014 and 2015. In August 2020, the gold price picked up to US$2060 per ounce after a total growth of 59% from August 2018 to October 2020, a period during which it outplaced the Nasdaq total return of 54%. Gold futures are traded on the COMEX exchange. These contacts are priced in USD per troy ounce (1 troy ounce = 31.1034768 grams). Below are the CQG contract specifications outlining the futures contracts:


Other applications


Jewelry

Because of the softness of pure (24k) gold, it is usually
alloy An alloy is a mixture of chemical elements of which in most cases at least one is a metal, metallic element, although it is also sometimes used for mixtures of elements; herein only metallic alloys are described. Metallic alloys often have prop ...
ed with other metals for use in jewelry, altering its hardness and ductility, melting point, color and other properties. Alloys with lower fineness#Karat, karat rating, typically 22k, 18k, 14k or 10k, contain higher percentages of copper, silver, palladium or other base metals in the alloy.Jewellery Alloys
World Gold Council
Nickel is toxic, and its release from nickel white gold is controlled by legislation in Europe. Palladium-gold alloys are more expensive than those using nickel. High-karat white gold alloys are more resistant to corrosion than are either pure silver or sterling silver. The Japanese craft of Mokume-gane exploits the color contrasts between laminated colored gold alloys to produce decorative wood-grain effects. By 2014, the gold jewelry industry was escalating despite a dip in gold prices. Demand in the first quarter of 2014 pushed turnover to $23.7 billion according to a
World Gold Council The World Gold Council is an international trade association for the gold industry. It is headquartered in London and has offices in India, China, Singapore, the UAE and the United States. The organization's members are gold mining companies. ...
report. Gold solder is used for joining the components of gold jewelry by high-temperature hard soldering or brazing. If the work is to be of hallmarking quality, the gold solder alloy must match the fineness of the work, and alloy formulas are manufactured to color-match yellow and white gold. Gold solder is usually made in at least three melting-point ranges referred to as Easy, Medium and Hard. By using the hard, high-melting point solder first, followed by solders with progressively lower melting points, goldsmiths can assemble complex items with several separate soldered joints. Gold can also be made into gold thread, thread and used in
embroidery Embroidery is the art of decorating Textile, fabric or other materials using a Sewing needle, needle to stitch Yarn, thread or yarn. It is one of the oldest forms of Textile arts, textile art, with origins dating back thousands of years across ...
.


Electronics

Only 10% of the world consumption of new gold produced goes to industry, but by far the most important industrial use for new gold is in fabrication of corrosion-free electrical connectors in computers and other electrical devices. For example, according to the World Gold Council, a typical cell phone may contain 50 mg of gold, worth about three dollars. But since nearly one billion cell phones are produced each year, a gold value of US$2.82 in each phone adds to US$2.82 billion in gold from just this application. (Prices updated to November 2022) Though gold is attacked by free chlorine, its good conductivity and general resistance to oxidation and corrosion in other environments (including resistance to non-chlorinated acids) has led to its widespread industrial use in the electronic era as a thin-layer coating on
electrical connector Components of an electrical circuit are electrically connected if an electric current can run between them through an electrical conductor. An electrical connector is an electromechanical device used to create an electrical connection between ...
s, thereby ensuring good connection. For example, gold is used in the connectors of the more expensive electronics cables, such as audio, video and USB cables. The benefit of using gold over other connector metals such as tin in these applications has been debated; gold connectors are often criticized by audio-visual experts as unnecessary for most consumers and seen as simply a marketing ploy. However, the use of gold in other applications in electronic sliding contacts in highly humid or corrosive atmospheres, and in use for contacts with a very high failure cost (certain computers, communications equipment, spacecraft, jet aircraft engines) remains very common. Besides sliding electrical contacts, gold is also used in electrical contacts because of its resistance to corrosion, electrical conductivity, ductile, ductility and lack of toxicity. Switch contacts are generally subjected to more intense corrosion stress than are sliding contacts. Fine gold wires are used to connect semiconductor devices to their packages through a process known as wire bonding. The concentration of free electrons in gold metal is 5.91×1022 cm−3. Gold is highly electrical conductivity, conductive to electricity and has been used for electrical wiring in some high-energy applications (only silver and copper are more conductive per volume, but gold has the advantage of corrosion resistance). For example, gold electrical wires were used during some of the Manhattan Project's atomic experiments, but large high-current silver wires were used in the calutron isotope separator magnets in the project. It is estimated that 16% of the world's presently-accounted-for gold and 22% of the world's silver is contained in electronic technology in Japan.


Medicine

There are only two gold compounds currently employed as pharmaceuticals in modern medicine (sodium aurothiomalate and auranofin), used in the treatment of arthritis and other similar conditions in the US due to their
anti-inflammatory Anti-inflammatory is the property of a substance or treatment that reduces inflammation, fever or swelling. Anti-inflammatory drugs, also called anti-inflammatories, make up about half of analgesics. These drugs reduce pain by inhibiting mechan ...
properties. These drugs have been explored as a means to help to reduce the pain and swelling of rheumatoid arthritis, and also (historically) against tuberculosis and some parasites. Some Western esotericism, esotericists and forms of alternative medicine assign metallic gold a healing power, against the scientific consensus. Historically, metallic and gold compounds have long been used for medicinal purposes. Gold, usually as the metal, is perhaps the most anciently administered medicine (apparently by shamanic practitioners) and known to Dioscorides. In medieval times, gold was often seen as beneficial for the health, in the belief that something so rare and beautiful could not be anything but healthy. In the 19th century gold had a reputation as an anxiolytic, a therapy for nervous disorders. Depression (mood), Depression, epilepsy, migraine, and glandular problems such as amenorrhea and impotence were treated, and most notably alcoholism (Keeley, 1897). The apparent paradox of the actual toxicology of the substance suggests the possibility of serious gaps in the understanding of the action of gold in physiology. Only salts and radioisotopes of gold are of pharmacological value, since elemental (metallic) gold is inert to all chemicals it encounters inside the body (e.g., ingested gold cannot be attacked by stomach acid). Gold alloys are used in restorative dentistry, especially in tooth restorations, such as Crown (dental restoration), crowns and permanent bridge (dentistry), bridges. The gold alloys' slight malleability facilitates the creation of a superior molar mating surface with other teeth and produces results that are generally more satisfactory than those produced by the creation of porcelain crowns. The use of gold crowns in more prominent teeth such as incisors is favored in some cultures and discouraged in others.
Colloidal gold Colloidal gold is a sol or colloidal suspension of nanoparticles of gold in a fluid, usually water. The colloid is coloured usually either wine red (for spherical particles less than 100  nm) or blue-purple (for larger spherical partic ...
preparations (suspensions of gold nanoparticles) in water are intensely red-colored, and can be made with tightly controlled particle sizes up to a few tens of nanometers across by reduction of gold chloride with citrate or ascorbate ions. Colloidal gold is used in research applications in medicine, biology and materials science. The technique of immunogold labeling exploits the ability of the gold particles to adsorb protein molecules onto their surfaces. Colloidal gold particles coated with specific antibodies can be used as probes for the presence and position of antigens on the surfaces of cells. In ultrathin sections of tissues viewed by electron microscope, electron microscopy, the immunogold labels appear as extremely dense round spots at the position of the antigen. Gold, or alloys of gold and
palladium Palladium is a chemical element; it has symbol Pd and atomic number 46. It is a rare and lustrous silvery-white metal discovered in 1802 by the English chemist William Hyde Wollaston. He named it after the asteroid Pallas (formally 2 Pallas), ...
, are applied as conductive coating to biological specimens and other non-conducting materials such as plastics and glass to be viewed in a scanning electron microscope. The coating, which is usually applied by sputtering with an argon plasma (physics), plasma, has a triple role in this application. Gold's very high electrical conductivity drains electric charge, electrical charge to earth, and its very high density provides stopping power for electrons in the electron beam, helping to limit the depth to which the electron beam penetrates the specimen. This improves definition of the position and topography of the specimen surface and increases the Angular resolution, spatial resolution of the image. Gold also produces a high output of secondary emission, secondary electrons when irradiated by an electron beam, and these low-energy electrons are the most commonly used signal source used in the scanning electron microscope. The isotope gold-198 (
half-life Half-life is a mathematical and scientific description of exponential or gradual decay. Half-life, half life or halflife may also refer to: Film * Half-Life (film), ''Half-Life'' (film), a 2008 independent film by Jennifer Phang * ''Half Life: ...
2.7 days) is used in nuclear medicine, in some cancer treatments and for treating other diseases.


Cuisine

* Gold can be used in food and has the E number 175. In 2016, the European Food Safety Authority published an opinion on the re-evaluation of gold as a food additive. Concerns included the possible presence of minute amounts of gold nanoparticles in the food additive, and that gold nanoparticles have been shown to be genotoxic in mammalian cells in vitro. * Gold leaf, flake or dust is used on and in some gourmet foods, notably sweets and drinks as decorative ingredient. Gold flake was used by the nobility in medieval Europe as a decoration in food and drinks. * Danziger Goldwasser (German: Gold water of Danzig) or Goldwasser () is a traditional German herbal liqueur produced in what is today Gdańsk, Poland, and Schwabach, Germany, and contains flakes of gold leaf. There are also some expensive (c. $1000) cocktails which contain flakes of gold leaf. However, since metallic gold is inert to all body chemistry, it has no taste, it provides no nutrition, and it leaves the body unaltered. * Vark is a Metal leaf, foil composed of a pure metal that is sometimes gold, and is used for Garnish (food), garnishing sweets in South Asian cuisine.


Miscellanea

* Gold produces a deep, intense red color when used as a coloring agent in cranberry glass. * In photography, gold toners are used to shift the color of silver bromide black-and-white prints towards brown or blue tones, or to increase their stability. Used on sepia tone, sepia-toned prints, gold toners produce red tones. Kodak published formulas for several types of gold toners, which use gold as the chloride. * Gold is a good reflector of electromagnetic radiation such as
infrared Infrared (IR; sometimes called infrared light) is electromagnetic radiation (EMR) with wavelengths longer than that of visible light but shorter than microwaves. The infrared spectral band begins with the waves that are just longer than those ...
and visible spectrum, visible light, as well as radio frequency, radio waves. It is used for the protective coatings on many artificial satellites, in infrared protective faceplates in thermal-protection suits and astronauts' helmets, and in electronic warfare planes such as the EA-6B Prowler. * Gold is used as the reflective layer on some Gold CD, high-end CDs. * Automobiles may use gold for heat shielding. McLaren uses gold foil in the engine compartment of its McLaren F1, F1 model. * Gold can be manufactured so thin that it appears semi-transparent. It is used in some aircraft cockpit windows for Deicing, de-icing or anti-icing by passing electricity through it. The heat produced by the resistance of the gold is enough to prevent ice from forming. * Gold is attacked by and dissolves in alkaline solutions of potassium or sodium
cyanide In chemistry, cyanide () is an inorganic chemical compound that contains a functional group. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom. Ionic cyanides contain the cyanide anion . This a ...
, to form the salt gold cyanide—a technique that has been used in extracting metallic gold from ores in the cyanide process. Gold cyanide is the electrolyte used in commercial
electroplating Electroplating, also known as electrochemical deposition or electrodeposition, is a process for producing a metal coating on a solid substrate through the redox, reduction of cations of that metal by means of a direct current, direct electric cur ...
of gold onto base metals and electroforming. * Gold chloride (
chloroauric acid Chloroauric acid is an inorganic compound with the chemical formula . It forms hydrates . Both the trihydrate and tetrahydrate are known. Both are orange-yellow solids consisting of the planar anion. Often chloroauric acid is handled as a solutio ...
) solutions are used to make colloidal gold by reduction with citrate or ascorbate ions. Gold chloride and gold oxide are used to make cranberry or red-colored glass, which, like colloidal gold suspensions, contains evenly sized spherical gold nanoparticles. * Gold, when dispersed in nanoparticles, can act as a Heterogeneous gold catalysis, heterogeneous catalyst of chemical reactions. * In recent years, gold has been used as a symbol of pride by the autism rights movement, as its symbol Au could be seen as similar to the word "Autism spectrum disorder, autism".


Toxicity

Pure metallic (elemental) gold is non-toxic and non-irritating when ingested and is sometimes used as a food decoration in the form of
gold leaf upA gold nugget of 5 mm (0.2 in) in diameter (bottom) can be expanded through hammering into a gold foil of about 0.5 m2 (5.4 sq ft). The Japan.html" ;"title="Toi gold mine museum, Japan">Toi gold mine museum, Japan. Gold leaf is gold that has ...
. Metallic gold is also a component of the alcoholic drinks Goldschläger, Gold Strike (drink), Gold Strike, and Goldwasser. Metallic gold is approved as a food additive in the EU (E number, E175 in the Codex Alimentarius). Although the gold ion is toxic, the acceptance of metallic gold as a food additive is due to its relative chemical inertness, and resistance to being corroded or transformed into soluble salts (gold compounds) by any known chemical process which would be encountered in the human body. Soluble compounds (
gold salts Gold-containing drugs are pharmaceuticals that contain gold. Sometimes these species are referred to as "gold salts". "Chrysotherapy" and "aurotherapy" are the applications of gold compounds to medicine. Research on the medicinal effects of g ...
) such as gold(I,III) chloride, gold chloride are toxic to the liver and kidneys. Common
cyanide In chemistry, cyanide () is an inorganic chemical compound that contains a functional group. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom. Ionic cyanides contain the cyanide anion . This a ...
salts of gold such as potassium gold cyanide, used in gold
electroplating Electroplating, also known as electrochemical deposition or electrodeposition, is a process for producing a metal coating on a solid substrate through the redox, reduction of cations of that metal by means of a direct current, direct electric cur ...
, are toxic by virtue of both their cyanide and gold content. There are rare cases of lethal gold poisoning from potassium gold cyanide. Gold toxicity can be ameliorated with chelation therapy with an agent such as dimercaprol. Gold metal was voted Allergen of the Year in 2001 by the American Contact Dermatitis Society; gold contact allergies affect mostly women. Despite this, gold is a relatively non-potent contact allergen, in comparison with metals like
nickel Nickel is a chemical element; it has symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive, but large pieces are slo ...
. A sample of the fungus ''Aspergillus niger'' was found growing from gold mining solution; and was found to contain cyano metal complexes, such as gold, silver, copper, iron and zinc. The fungus also plays a role in the solubilization of heavy metal sulfides.


See also

* Bulk leach extractable gold, for sampling ores * Chrysiasis (dermatological condition) * Digital gold currency, form of electronic currency * GFMS business consultancy * Gold fingerprinting, use impurities to identify an alloy *
Gold standard A gold standard is a backed currency, monetary system in which the standard economics, economic unit of account is based on a fixed quantity of gold. The gold standard was the basis for the international monetary system from the 1870s to the ...
in banking * List of countries by gold production * Tumbaga, alloy of gold and copper * Iron pyrite, fool's gold * Nordic gold, non-gold copper alloy


References


Further reading

* Bachmann, H. G. ''The lure of gold : an artistic and cultural history'' (2006
online
* Bernstein, Peter L. ''The Power of Gold: The History of an Obsession'' (2000
online
* Brands, H.W. ''The Age of Gold: The California Gold Rush and the New American Dream'' (2003
excerpt
* Buranelli, Vincent. ''Gold : an illustrated history'' (1979
online
wide-ranging popular history * Cassel, Gustav. "The restoration of the gold standard." ''Economica'' 9 (1923): 171–185
online
* Eichengreen, Barry. ''Golden Fetters: The Gold Standard and the Great Depression, 1919–1939'' (Oxford UP, 1992). * Ferguson, Niall. ''The Ascent of Money – Financial History of the World'' (2009
online
* Hart, Matthew
Gold: The Race for the World's Most Seductive Metal
''Gold : the race for the world's most seductive metal", New York: Simon & Schuster, 2013. '' * * Kwarteng, Kwasi. ''War and Gold: A Five-Hundred-Year History of Empires, Adventures, and Debt'' (2014
online
* Vilar, Pierre. ''A History of Gold and Money, 1450–1920'' (1960)
online
* Vilches, Elvira. ''New World Gold: Cultural Anxiety and Monetary Disorder in Early Modern Spain'' (2010).


External links

*
Chemistry in its element podcast
(MP3) from the Royal Society of Chemistry's Chemistry World
Gold
www.rsc.org

at ''The Periodic Table of Videos'' (University of Nottingham)
''Getting Gold'' 1898 book
www.lateralscience.co.uk * , www.epa.gov
Gold element information
– rsc.org {{Authority control Gold, Chemical elements Transition metals Noble metals Precious metals Cubic minerals Minerals in space group 225 Dental materials Electrical conductors Native element minerals E-number additives Symbols of Alaska Symbols of California Chemical elements with face-centered cubic structure Coinage metals and alloys Symbols of Victoria