Tennantite is a

copper Copper is a chemical element with the symbol Cu (from la, cuprum) 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 pinkis ...

arsenic Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but ...

sulfosalt mineral Sulfosalt minerals are sulfide minerals with the general formula , where *A represents a metal such as copper, lead, silver, iron, and rarely mercury (element), mercury, zinc, vanadium *B usually represents semi-metal such as arsenic, antimony, b ...

with an ideal formula . Due to variable substitution of the copper by

iron Iron () is a chemical element with symbol Fe (from la, ferrum) 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, right in f ...

and

zinc Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...

the formula is . It is gray-black, steel-gray, iron-gray or black in color. A closely related mineral,

tetrahedrite Tetrahedrite is a copper antimony sulfosalt mineral with formula: . It is the antimony endmember of the continuous solid solution series with arsenic-bearing tennantite. Pure endmembers of the series are seldom if ever seen in nature. Of the two, ...

) has

antimony Antimony is a chemical element with the symbol Sb (from la, stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient time ...

substituting for arsenic and the two form a

solid solution A solid solution, a term popularly used for metals, is a homogenous mixture of two different kinds of atoms in solid state and have a single crystal structure. Many examples can be found in metallurgy, geology, and solid-state chemistry. The word ...

series. The two have very similar properties and is often difficult to distinguish between tennantite and tetrahedrite.

Iron Iron () is a chemical element with symbol Fe (from la, ferrum) 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, right in f ...

, and

silver Silver is a chemical element with the Symbol (chemistry), symbol Ag (from the Latin ', derived from the Proto-Indo-European wikt:Reconstruction:Proto-Indo-European/h₂erǵ-, ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, whi ...

substitute up to about 15% for the copper site. The mineral was first described for an occurrence in

Cornwall Cornwall (; kw, Kernow ) is a historic county and ceremonial county in South West England. It is recognised as one of the Celtic nations, and is the homeland of the Cornish people. Cornwall is bordered to the north and west by the Atlantic ...

England England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...

in 1819, where it occurs as small crystals of cubic or dodecahedral form, and was named after the English chemist

Smithson Tennant Smithson Tennant FRS (30 November 1761 – 22 February 1815) was an English chemist. He is best known for his discovery of the elements iridium and osmium, which he found in the residues from the solution of platinum ores in 1803. He also cont ...

(1761–1815). It is found in

hydrothermal Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

veins Veins are blood vessels in 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 the pulmonary and umbilical veins, both of which carry oxygenated b ...

and

contact Contact may refer to: Interaction Physical interaction * Contact (geology), a common geological feature * Contact lens or contact, a lens placed on the eye * Contact sport, a sport in which players make contact with other players or objects * ...

metamorphic Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causin ...

deposits in association with other Cu–Pb–Zn–Ag sulfides and sulfosalts,

pyrite 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 Luster (mineralogy), lust ...

calcite Calcite is a Carbonate minerals, carbonate mineral and the most stable Polymorphism (materials science), polymorph of calcium carbonate (CaCO3). It is a very common mineral, particularly as a component of limestone. Calcite defines hardness 3 on ...

dolomite Dolomite may refer to: *Dolomite (mineral), a carbonate mineral *Dolomite (rock), also known as dolostone, a sedimentary carbonate rock *Dolomite, Alabama, United States, an unincorporated community *Dolomite, California, United States, an unincor ...

siderite Siderite is a mineral composed of iron(II) carbonate (FeCO3). It takes its name from the Greek word σίδηρος ''sideros,'' "iron". It is a valuable iron mineral, since it is 48% iron and contains no sulfur or phosphorus. Zinc, magnesium and ...

barite Baryte, barite or barytes ( or ) is a mineral consisting of barium sulfate ( Ba S O4). Baryte is generally white or colorless, and is the main source of the element barium. The ''baryte group'' consists of baryte, celestine (strontium sulfate), ...

fluorite Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon. The Mohs sca ...

and

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...

. The arsenic component of tennantite causes the metal

smelted Smelting is a process of applying heat to ore, to extract a base metal. It is a form of extractive metallurgy. It is used to extract many metals from their ores, including silver, iron, copper, and other base metals. Smelting uses heat and a c ...

from the ore to be harder than that of pure copper, because it is a copper-arsenic

alloy An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, ...

. In the later 20th century it was found that arsenical coppers had been more widely used in antiquity than had been previously realised, and it has been proposed that discoveries made by smelting ores like tennantite were significant steps in the progress towards the

Bronze Age The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second pri ...

References

Copper ores Sulfosalt minerals Cubic minerals Minerals in space group 217 {{sulfide-mineral-stub

See also

References