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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 also known as "Colored gold#Green gold, green gold".Emsley, John (2003Nature's building blocks: an A–Z guide to the elements Oxford University Press. p. 168. . Electrum was used as early as the third millennium BC in the Old Kingdom of Egypt, sometimes as an exterior coating to the pyramidion, pyramidia atop ancient Egyptian pyramids and obelisks. It was also used in the making of ancient Beaker (archaeology) , drinking vessels. The first known metal coins made were of electrum, dating back to the end of the 7th century or the beginning of the 6th century BC. Etymology The name ''electrum'' is the Latinized form of the Greek language, Greek word ἤλεκτρον (''ḗlektron''), mentioned in the ''Odyssey'', referring to a metallic s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coin
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 a government. Coins often have images, numerals, or text on them. The faces of coins or medals are sometimes called the ''obverse'' and the ''reverse'', referring to the front and back sides, respectively. The obverse of a coin is commonly called ''heads'', because it often depicts the head of a prominent person, and the reverse is known as ''tails''. The first metal coins – invented in the ancient Greek world and disseminated during the Hellenistic period – were precious metal–based, and were invented in order to simplify and regularize the task of measuring and weighing bullion (bulk metal) carried around for the purpose of transactions. They carried their value within the coins themselves, but the stampings also induced manip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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. Silver is found in the Earth's crust in the pure, free elemental form ("native metal, native silver"), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc Refining (metallurgy), refining. Silver has long been valued as a precious metal. Silver metal is used in many bullion coins, sometimes bimetallism, alongside gold: while it is more abundant than gold, it is much less abundant as a native metal. Its purity is typically measured on a per-mille basis; a 94%-pure alloy is described as "0.940 fine". As one of the seven metals of antiquity, silver has had an enduring role in most human cultures. Other than in currency and as an in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colored Gold
Colored Gold is the name given to any gold that has been treated using techniques to change its natural color. Pure gold is slightly reddish yellow in color, but colored gold can come in a variety of different colors by alloying it with different elements. Colored golds can be classified in three groups: * Alloys with silver and copper in various proportions, producing white, yellow, green and red golds. These are typically malleable alloys. * Intermetallic compounds, producing blue and purple golds, as well as other colors. These are typically brittle, but can be used as gems and inlays. * Surface treatments, such as oxide layers. Pure 100% (in practice, 99.9% or better) gold is 24 karat by definition, so all colored golds are less pure than this, commonly 18K (75%), 14K (58.5%), 10K (41.6%), or 9K (37.5%). Alloys White gold The word ''white'' covers a broad range of colors that borders or overlaps pale yellow, tinted brown, and even very pale rose. White gold is an alloy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amber
Amber is fossilized tree resin. Examples of it have been appreciated for its color and natural beauty since the Neolithic times, and worked as a gemstone since antiquity."Amber" (2004). In Maxine N. Lurie and Marc Mappen (eds.) ''Encyclopedia of New Jersey'', Rutgers University Press, . Amber is used in jewelry and as a healing agent in Traditional medicine, folk medicine. There are five classes of amber, defined on the basis of their chemical constituents. Because it originates as a soft, sticky tree resin, amber sometimes contains animal and plant material as Inclusion (mineral), inclusions. Amber occurring in coal seams is also called resinite, and the term ''ambrite'' is applied to that found specifically within New Zealand coal seams. Etymology The English word ''amber'' derives from Arabic from Middle Persian 𐭠𐭭𐭡𐭫 (''ʾnbl'' /ambar/, “ambergris”) via Medieval Latin, Middle Latin ''ambar'' and Middle French ''ambre''. The word referred to what is n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gold
Gold is a chemical element; it has chemical symbol Au (from Latin ) and atomic number 79. In its pure form, it is a brightness, bright, slightly orange-yellow, dense, soft, malleable, and ductile metal. Chemically, gold is a transition metal, a group 11 element, and one of the noble metals. It is one of the least reactivity (chemistry), reactive chemical elements, being the second-lowest in the reactivity series. It is solid under standard temperature and pressure, standard conditions. Gold often occurs in free elemental (native state (metallurgy), native state), as gold nugget, nuggets or grains, in rock (geology), rocks, vein (geology), veins, and alluvial deposits. It occurs in a solid solution series with the native element silver (as in electrum), naturally alloyed with other metals like copper and palladium, and mineral inclusions such as within pyrite. Less commonly, it occurs in minerals as gold compounds, often with tellurium (gold tellurides). Gold is resistant to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 properties that differ from those of the pure elements from which they are made. The vast majority of metals used for commercial purposes are alloyed to improve their properties or behavior, such as increased strength, hardness or corrosion resistance. Metals may also be alloyed to reduce their overall cost, for instance alloys of gold and Copper(II) sulfate, copper. A typical example of an alloy is SAE 304 stainless steel, 304 grade stainless steel which is commonly used for kitchen utensils, pans, knives and forks. Sometime also known as 18/8, it as an alloy consisting broadly of 74% iron, 18% chromium and 8% nickel. The chromium and nickel alloying elements add strength and hardness to the majority iron element, but their main function is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mytilene
Mytilene (; ) is the capital city, capital of the Greece, Greek island of Lesbos, and its port. It is also the capital and administrative center of the North Aegean Region, and hosts the headquarters of the University of the Aegean. It was founded in the 11th century BC. Mytilene is one of the two municipalities and communities of Greece, municipalities on the island of Lesbos, created in 2019; the other is West Lesbos. Mytilene is built on the southeast edge of the island. It is the seat of a metropolitan bishop of the Greek Orthodox Church. History As an ancient city, lying off the east coast, Mytilene was initially confined to a small island just offshore that later was joined to Lesbos, creating a north and south harbor. The early harbors of Mytilene were linked during ancient times by a channel 700 m long and 30 m wide. The Roman writer Longus speaks of white stone bridges linking the two sides. The Greek word εὔριπος ''eúripos'' is a commonly-used term when ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electron
The electron (, or in nuclear reactions) is a subatomic particle with a negative one elementary charge, elementary electric charge. It is a fundamental particle that comprises the ordinary matter that makes up the universe, along with up quark, up and down quark, down quarks. Electrons are extremely lightweight particles that orbit the positively charged atomic nucleus, nucleus of atoms. Their negative charge is balanced by the positive charge of protons in the nucleus, giving atoms their overall electric charge#Charge neutrality, neutral charge. Ordinary matter is composed of atoms, each consisting of a positively charged nucleus surrounded by a number of orbiting electrons equal to the number of protons. The configuration and energy levels of these orbiting electrons determine the chemical properties of an atom. Electrons are bound to the nucleus to different degrees. The outermost or valence electron, valence electrons are the least tightly bound and are responsible for th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phocaea
Phocaea or Phokaia (Ancient Greek language, Ancient Greek: Φώκαια, ''Phókaia''; modern-day Foça in Turkey) was an ancient Ionian Ancient Greece, Greek city on the western coast of Anatolia. Colonies in antiquity, Greek colonists from Phocaea founded the colony of Massalia (modern-day Marseille, in France) in 600 BC, Emporion (modern-day Empúries, in Catalonia, Spain) in 575 BC and Elea (modern-day Velia, in Campania, Italy) in 540 BC. Geography Phocaea was the northernmost of the Ionian cities, on the boundary with Aeolis. It was located near the mouth of the river Hermus (now Gediz River, Gediz), and situated on the coast of the peninsula separating the Gulf of Cyme (Aeolis), Cyme to the north, named for the largest of the Aeolis, Aeolian cities, and the Gulf of Smyrna (now İzmir) to the south. Phocaea had two natural harbours within close range of the settlement, both containing a number of small islands. Phocaea's harbours allowed it to develop a thriv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyramid
A pyramid () is a structure whose visible surfaces are triangular in broad outline and converge toward the top, making the appearance roughly a pyramid in the geometric sense. The base of a pyramid can be of any polygon shape, such as triangular or quadrilateral, and its surface-lines either filled or stepped. A pyramid has the majority of its mass closer to the ground with less mass towards the pyramidion at the apex. This is due to the gradual decrease in the cross-sectional area along the vertical axis with increasing elevation. This offers a weight distribution that allowed early civilizations to create monumental structures.Ancient civilizations in many parts of the world pioneered the building of pyramids. The largest pyramid by volume is the Mesoamerican Great Pyramid of Cholula, in the Mexican state of Puebla. For millennia, the largest structures on Earth were pyramids—first the Red Pyramid in the Dashur Necropolis and then the Great Pyramid of Khufu, bot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Πακτωλός
Pactolus (), also called Chrysorrhoas (Χρυσορρόας), the modern Sart Çayı , is a river near the Aegean coast of Turkey. The river rises from Mount Tmolus, flows through the ruins of the ancient city of Sardis, and empties into the Gediz River, the ancient Hermus. The Pactolus once contained electrum that was the basis of the economy of the ancient state of Lydia, which used the naturally occurring alloy of gold and silver to mint the first coins under Alyattes of Lydia. Name Pseudo-Plutarch in the De fluviis writes that the river was initially called Chrysorrhoas (Χρυσορρόας ) because according to the legend, Chrysorrhoas (the son of Apollo) threw himself into the river. Later it was called Pactolus, from Pactolus, the son of Leucothea, who during a festival of Aphrodite failed to recognize his own sister, Demodice, and ravished her. Upon realizing what he had done, overwhelmed with grief, he threw himself into the river. Because of this the name of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
