Home About us Products Services Contact us Bookmark
:: wikimiki.org ::
Copper

Copper

Copper is a chemical element in the periodic table that has the symbol Cu and atomic number 29.

History

In Greek times, the metal was known by the name chalkos (χαλκός). Copper was a very important resource for the Romans and Greeks. In Roman times, it became known as aes Cyprium (aes being the generic Latin term for copper alloys such as bronze and other metals, and Cyprium because so much of it was mined in Cyprus). From this, the phrase was simplified to cuprum and then eventually Anglicized into the English copper. Copper was known to some of the oldest civilizations on record, and has a history of use that is at least 10,000 years old. A copper pendant was found in what is now northern Iraq that dates to 8700 BC. By 5000 BC there are signs of copper smelting, the refining of copper from simple copper oxides such as malachite or azurite. The earliest signs of gold use, by contrast, appear around 4000 BC. There are copper and bronze artifacts from Sumerian cities that date to 3000 BC, and Egyptian artifacts in copper and copper alloyed with tin nearly as old. In one pyramid, a copper plumbing system was found that is 5000 years old. tin The Egyptians found that adding a small amount of tin made the metal easier to cast, so bronze alloys are found in Egypt almost as soon as copper is found. Use of copper in ancient China dates to at least 2000 BC. By 1200 BC excellent bronzes were being made in China. Note that these dates are affected by wars and conquest, as copper is easily melted down and reused. In Europe, Oetzi the Iceman, a well preserved male dated to 3200 BC, was found with a copper tipped axe whose metal was 99.7% pure. High levels of arsenic in his hair suggests he was involved in copper smelting. The use of bronze was so pervasive in a certain era of civilization that it has been named the Bronze Age. The transitional period in certain regions between the preceding Neolithic period and the Bronze Age is termed the Chalcolithic, with some high purity copper tools being used alongside stone tools. Chalcolithic Brass, an alloy of zinc and copper, was known to the Greeks but first used extensively by the Romans. Copper was associated with the goddess Aphrodite/Venus in mythology and alchemy, owing to its lustrous beauty, its ancient use in producing mirrors, and its association with Cyprus, which was sacred to the goddess. In alchemy the symbol for copper was also the symbol for the planet Venus.

Biological role

Copper is essential in all higher plants and animals. Copper is carried mostly in the bloodstream on a plasma protein called ceruloplasmin. When copper is first absorbed in the gut it is transported to the liver bound to albumin. Copper is found in a variety of enzymes, including the copper centers of cytochrome c oxidase and the enzyme superoxide dismutase (containing copper and zinc), and is the central metal in the oxygen carrying pigment hemocyanin. The blood of the horseshoe crab, Limulus polyphemus, uses copper rather than iron for oxygen transport. [http://www.ocean.udel.edu/horseshoecrab/funFacts.html] It is believed that zinc and copper compete for absorption in the digestive tract so that a diet that is excessive in one of these minerals may result in a deficiency in the other. The RDA for copper in normal healthy adults is 0.9 mg/day.

Toxicity

All copper compounds, unless otherwise known, should be treated as if they were toxic. 30g of copper sulfate is potentially lethal in humans. The suggested safe level of copper in drinking water for humans varies depending on the source, but tends to be pegged at 1.5 to 2 mg/l. The DRI Tolerable Upper Intake Level for adults of dietary copper from all sources is 10 mg/day.In toxicity, copper can inhibit the enzyme dihydrophil hydratase, an enzyme involved in haemopoesis An inherited condition called Wilson's disease causes the body to retain copper, since it is not excreted by the liver into the bile. This disease, if untreated, can lead to brain and liver damage. In addition, studies have found that people with mental illnesses such as schizophrenia had heightened levels of copper in their systems. However it is unknown at this stage whether the copper contributes to the mental illness, whether the body attempts to store more copper in response to the illness, or whether the high levels of copper are the result of the mental illness.

Miscellaneous hazards

The metal, when powdered, is a fire hazard. At concentrations higher than 1 mg/L, copper can stain clothes and items washed in water.

Physical characteristics

fire hazard Copper is a reddish-coloured metal, with a high electrical and thermal conductivity (among pure metals at room temperature, only silver has a higher electrical conductivity). Copper has its characteristic color because it reflects red and orange light and absorbs other frequencies in the visible spectrum, due to its band structure. There are two stable isotopes, 63Cu and 65Cu, along with a couple dozen radioisotopes. The vast majority of radioisotopes have half lives on the order of minutes or less; the longest lived, 64Cu, has a half life of 12.7 hours, with two decay modes, leading to two separate products. There are numerous alloys of copper - speculum metal is a copper/tin alloy, brass is a copper/zinc alloy, and bronze is a copper/tin alloy. Monel metal is a copper/nickel alloy, also called cupronickel.

Compounds

cupronickel Common oxidation states of copper include the less stable copper(I) state, Cu+1; and the more stable copper(II) state, Cu+2, which forms lovely blue or blue-green salts. Under unusual conditions, a +3 state can be obtained. Copper(II) carbonate is green from which arises the unique appearance of copper-clad roofs or domes on some buildings. Copper(II) sulfate forms a blue crystalline pentahydrate which is perhaps the most familiar copper compound in the laboratory. It is used as a fungicide, known as Bordeaux mixture. There are two stable copper oxides, copper(II) oxide (CuO) and copper(I) oxide (Cu2O). Copper oxides are used to make yttrium barium copper oxide (YBa2Cu3O7-δ) or YBCO which forms the basis of many unconventional superconductors. Copper (I) compounds : copper(I) chloride, copper(I) oxide. Copper (II) compounds : copper(II) carbonate, copper(II) chloride, copper(II) hydroxide, copper(II) nitrate, copper(II) oxide, copper(II) sulfate, copper(II) sulfide. Copper (I) and Copper (II) can also be referred to by their common names cuprous and cupric.

Occurrence

copper(II) sulfide :See Copper extraction for the main article. Copper can be found as native copper in mineral form. Minerals such as the carbonates azurite (Cu3(CO3)2(OH)2) and malachite (Cu2CO3(OH)2) are sources of copper, as are sulfides such as chalcopyrite (CuFeS2), bornite (Cu5FeS4), covellite (CuS), chalcocite (Cu2S) and oxides like cuprite (Cu2O). Most copper ore is mined or extracted from large open pit mines in copper porphyry deposits that contain 0.4 to 1.0 percent copper. Examples include: Chuquicamata in Chile and El Chino mine in New Mexico. The average abundance of copper found within crustal rocks is approximately 68000 parts per billion by mass, and 22000 parts per billion by atoms. The Intergovernmental Council of Copper Exporting Countries (CIPEC), defunct since 1992, once tried to play a similar role for copper as OPEC does for oil, but never achieved the same influence, not least because the second-largest producer, the United States, was never a member. Formed in 1967, its principal members were Chile, Peru, Zaire, and Zambia.

Tests for copper2+ ion

Add aqueous sodium hydroxide. A blue precipitate of copper(II) hydroxide should form, by the displacement of the copper ions by sodium ions. Ionic equation: :Cu2+(aq) + 2OH-(aq) -> Cu(OH)2 (s) Add aqeuous ammonia. A precipitate should form, which then dissolves upon adding excess ammonia, to form an ammonia complex, tetraaminecopper(II). Ionic equation: :Cu2+(aq) + 4NH3 (aq) -> Cu(NH3)42+(aq)

Applications

Copper is malleable and ductile, and is used extensively, in products such as:
- Copper wire.
- Copper plumbing.
- Doorknobs and other fixtures in houses.
- Statuary: The Statue of Liberty, for example, contains 179,200 pounds (81.3 tonnes) of copper.
- Electromagnets.
- Motors, especially electromagnetic motors.
- Watt's steam engine.
- Electrical relays, electrical busbars and electrical switches.
- Vacuum tubes, cathode ray tubes, and the magnetrons in microwave ovens.
- Wave guides for microwave radiation.
- There is increasing use of copper in integrated circuits, replacing aluminium because of its superior conductivity.
- Alloyed with nickel, e.g. cupronickel and Monel, used as corrosive resistant materials in shipbuilding.
- As a component of coins, often as cupronickel alloy.
- In cookware, such as frying pans.
- Most flatware (knives, forks, spoons) contains some copper (nickel silver).
- Sterling silver, if it is to be used in dinnerware, must contain a few percent copper.
- As a component in ceramic glazes, and to color glass.
- Musical instruments, especially brass instruments.
- As a biostatic surface in hospitals, and to line parts of ships to protect against barnacles and mussels, originally used pure, but superceded by Muntz Metal. Bacteria will not grow on a copper surface because it is biostatic. Copper doorknobs are used by hospitals to reduce the transfer of disease, and Legionnaire's Disease is supressed by copper tubing in air-conditioning systems.
- Compounds, such as Fehling's solution, have applications in chemistry.
- Copper(II) sulfate is used as a poison and a water purifier. It is used in gardening powders and sprays to kill mildew.
- As a material in the manufacture of computer heatsinks, as a result of its superior heat dissipation capacity to aluminium.

References


- [http://periodic.lanl.gov/elements/29.html Los Alamos National Laboratory - Copper]
- Copper: Technology & Competitiveness (Summary) Chapter 6: Copper Production Technology; Author: Office of Technology Assessment 2005
- [http://www.ocean.udel.edu/horseshoecrab/funFacts.html NOAA and Univ. of Delaware, Horseshoe Crab Fun Facts] Accessed 12-12-2005.

External links


- [http://www.webelements.com/webelements/elements/text/Cu/index.html WebElements.com – Copper]
- [http://www.healingedge.net/briefs_copper_tox.html Copper Toxicity Syndrome]
- [http://www.best-home-remedies.com/minerals/copper.htm Copper- Benefits, Deficiency Symptoms And Food Sources]
- [http://www.copper.org/ The Copper Page]
- [http://y2u.co.uk/&002_Images/Parys_Mountain_01.htm Photos of the Parys Mountain Copper Mine near Amlwch, Anglesey, Wales]
- [http://www.gindre.com/cours_du_cuivre/l_home.htm Current copper price] as at June 2005, about USD$3,500 / tonne.
- [http://www.indexmundi.com/en/commodities/minerals/copper/copper_t20.html World mine production of copper by country] Category:Chemical elements Category:Transition metals ko:구리 ja:銅 simple:Copper th:ทองแดง

Chemical element

A chemical element, often called simply element, is a chemical substance that canot be divided or changed into other chemical substances by any ordinary chemical technique. The smallest unit of this kind of chemical substances is an atom. An element is a class of substances that contain the same number of protons in all its atoms.

Chemistry terminology

Earlier an element or pure element was defined as a substance which "cannot be further broken down into another compound with different chemical properties" -- which should be taken to mean it consists of atoms of one element. However, due to allotropy, the isotope effect, and the confusion with the more useful term referring to the general class of atoms (irrespective of what compound it may be in), this usage is in disfavor amongst contemporary chemists, and sees restricted, mostly historical, use. This definition was motivated by the observation that these elements could not be dissociated by chemical means into other compounds. For example, water could be converted into hydrogen and oxygen, but hydrogen and oxygen could not be further decomposed, thus "elemental". There are also many counterexamples (for example "elemental oxygen" (O2) can be decomposed by solely chemical means into oxygen ions and atoms which have drastically different chemical properties). The remainder of this article will concern itself with the first definition.

Description

The atomic number of an element, Z, is equal to the number of protons which defines the element. For example, all carbon atoms contain 6 protons in their nucleus, so for carbon Z=6. These atoms may have different amounts of neutrons, and are known as isotopes of the element. The atomic mass of an element, A, is measured in unified atomic mass units (u) is the average mass of all the atoms of the element in an environment of interest (usually the earth's crust and atmosphere). Since electrons are light, and neutrons are barely more than the mass of the proton, this usually corresponds to the sum of the protons and neutrons in the nucleus of the most abundant isotope, though this is not always the case (notably chlorine, which is about three-quarters 35Cl and a quarter 37Cl). Some isotopes are radioactive and decay into other elements upon radiating an alpha or beta particle. Some elements have no nonradioactive isotopes, in particular all elements with Z >= 84. The lightest elements are hydrogen and helium. Hydrogen is thought to be the first element to appear after the Big Bang. All the heavier elements, are made naturally and artificially through various methods of nucleosynthesis. As of 2005, there are 116 known elements: 93 occur naturally on earth (including technetium and plutonium), and 94 (including promethium) have been detected so far in the universe. The 23 elements not found on earth are derived artificially; the first purportedly synthesized element was technetium, in 1937, although the trace amounts of naturally occurring technetium were not known then. All artificially derived elements are radioactive with short half-lives so that any such atoms that were present at the formation of Earth are extremely likely to have already decayed. Lists of the elements by name, by symbol, by atomic number, by density, by melting point and by boiling point are available. The most convenient presentation of the elements is in the periodic table, which groups elements with similar chemical properties together.

Nomenclature

The naming of elements precedes the atomic theory of matter, although at the time it was not known which chemicals were elements and which compounds. When it was learned, existing names (e.g., gold, mercury, iron) were kept in most countries, and national differences emerged over the names of elements either for convenience, linguistic niceties, or nationalism. For example, the Germans use "Wasserstoff" for "hydrogen" and "Sauerstoff" for "oxygen," while some romance languages use "natrium" for "sodium" and "kalium" for "potassium," and the French prefer the obsolete but historic term "azote" for "nitrogen." But for international trade, the official names of the chemical elements both ancient and recent are decided by the International Union of Pure and Applied Chemistry, which has decided on a sort of international English language. That organization has recently prescribed that "aluminium" and "caesium" take the place of the US spellings "aluminum" and "cesium," while the US "sulfur" takes the place of the British "sulphur." But chemicals which are practicable to be sold in bulk within many countries, however, still have national names, and those which do not use the Latin alphabet cannot be expected to use the IUPAC name. According to IUPAC, the full name of an element is not capitalized, even if it is derived from a proper noun (unless it would be capitalized by some other rule, for instance if it begins a sentence). And in the second half of the twentieth century physics laboratories became able to produce nuclei of chemical elements that have too quick a decay rate to ever be sold in bulk. These are also named by IUPAC, which generally adopts the name chosen by the discoverer. This can lead to the controversial question of which research group actually discovered an element, a question which delayed the naming of elements with atomic number of 104 and higher for a considerable time. (See element naming controversy). Precursors of such controversies involved the nationalistic namings of elements in the late nineteenth century (e.g., as "lutetium" refers to Paris, France, the Germans were reticent about relinquishing naming rights to the French, often calling it "cassiopeium"). And notably, the British discoverer of "niobium" originally named it "columbium," after the New World, though this did not catch on in Europe. The Americans had to accept the international name just when it was becoming an economically important material late in the twentieth century.

Chemical symbols

Specific chemical elements

Before chemistry became a science, alchemists had designed arcane symbols for both metals and common compounds. These were however used as abbreviations in diagrams or procedures; there was no concept of one atoms combining to form molecules. With his advances in the atomic theory of matter, John Dalton devised his own simpler symbols, based on circles, which were to be used to depict molecules. These were superseded by the current typographical system in which chemical symbols are not used as mere abbreviations though each consists letters of the Latin alphabet - they are symbols intended to be used by peoples of all languages and alphabets. The first of these symbols were intended to be fully international, for they were based on the Latin abbreviations of the names of metals: Fe comes from Ferrum; Ag from Argentum. The symbols were not followed by a period (full stop) as abbreviations were. Besides a name, later chemical elements are also given a unique chemical symbol, based on the name of the element, not necessarily derived from the colloquial English name. (e.g., sodium has chemical symbol 'Na' after the Latin natrium). The same applies to "W" (wolframium) for Tungsten , "Hg" (Hydrargyrum) for mercury and "K" for potassium. Stricly taken, a symbol like Tu for tungsten or M or Me for mercury seems to be more logical. Chemical symbols are understood internationally when element names might need to be translated. There are sometimes differences; for example, the Germans have used "J" instead of "I" for iodine, so the character would not be confused with a roman numeral. The first letter of a chemical symbol is always capitalized, as in the preceding examples, and the subsequent letters, if any, are always minuscule (small letters).

General chemical symbols

There are also symbols for series of chemical elements, for comparative formulas. These are one capital letter in length, and the letters are reserved so they are not permitted to be given for the names of specific elements. For example, an "X" is used to indicate a variable group amongst a class of compounds (though usually a halogen), while "R" is used for a radical (not to be confused with radical_(chemistry), meaning a compound structure such as a hydrocarbon chain. The letter "Q" is reserved for "heat" in a chemical reaction. "Y" is also often used as a general chemical symbol, although it is also the symbol of Yttrium. "Z" is also frequently used as a general variable group. "L" is used to represent a general ligand in inorganic and organometallic chemistry. "M" is also often used in place of a general metal.

Nonelement symbols

Nonelements, especially in organic and organometallic chemistry, often acquire symbols which are inspired by the elemental symbols. A few examples: Cy - cyclohexyl; Ph - phenyl; Bz - benzoyl; Bn - benzyl; Cp - Cyclopentadiene; Pr - propyl; Me - methyl; Et - ethyl; Tf - triflate; Ts - tosyl.

See also


- Abundance of the chemical elements
- Compound
- Chemical elements named after people
- Chemical elements named after places
- Chemistry
- Discovery of the chemical elements
- Elements song
- Fictional element
- Periodic table
- Systematic element name
- Chemistry resources
- Table of chemical elements

External links


- [http://www.vanderkrogt.net/elements/ Elementymology & Elements Multidict] word history and language dictionary

Chemical information


- [http://www.webelements.com/ WebElements]
- [http://www.vcs.ethz.ch/chemglobe/ptoe/ ChemGlobe]
- [http://pearl1.lanl.gov/periodic/default.htm Los Alamos National Laboratory]
- [http://www.chemicalelements.com/ ChemicalElements] ko:화학 원소 ms:Unsur kimia ja:元素 simple:Element th:ธาตุเคมี



Bronze

Bronze is the ancient name for a broad range of alloys of copper, but usually with tin as the main additive. First used in the Bronze Age, it made tools, weapons and armor harder or more durable than their stone and copper predecessors. In early use, the impurity arsenic made the alloy even harder. The earliest bronzes date to the late 4th millennium BC in Susa (Iran) and some ancient sites in Luristan (Iran) and Mesopotamia (Iraq). Bronze was stronger than the era's iron; quality steels were not available until thousands of years later. But the Bronze Age gave way to the Iron Age, perhaps because the shipping of tin around the Mediterranean became more limited during the major population migrations around 1200 – 1100 BC, which dramatically limited supplies and raised prices.[http://www.claytoncramer.com/Iron2.pdf] Bronze was still used during the Iron Age, but for many purposes the weaker iron was sufficiently strong. As ironworking improved, iron became both cheaper and stronger, eclipsing bronze in Europe by the early to mid-Middle Ages. Copper-based alloys have lower melting points than steel and are more readily produced from their constituent metals. They are generally about 10 percent heavier than steel, although alloys using aluminium or silicon may be slightly less dense. Bronzes are softer and weaker than steel, and more elastic, though bronze springs are less stiff (lower energy) for the same bulk. Bronzes resist corrosion (especially seawater corrosion) and metal fatigue better than steel. Bronzes also conduct heat and electricity better than most steels. The cost of copper-base alloys is generally higher than that of steels but lower than that of nickel-base alloys. Copper and its alloys have a huge variety of uses that reflect their versatile physical, mechanical, and chemical properties. Some common examples are the high electrical conductivity of pure copper, the excellent deep-drawing qualities of cartridge case brass, the low-friction properties of bearing bronze, the resonant qualities of bell bronze, and the resistance to corrosion by sea water by several bronze alloys. In the twentieth century, silicon was introduced as the primary alloying element, creating an alloy with wide application in industry and the major form used in contemporary statuary. Aluminium is also used for the structural metal Aluminium bronze. Bronze is the most popular metal for top-quality bells and cymbals, and also for cast metal sculpture (see bronze sculpture). Common bronze alloys often have the unusual and very desirable property of expanding slightly just before they set, thus filling in the finest details of a mould. Bronze also has very little metal-on-metal friction, which made it invaluable for the building of cannon where iron cannonballs would otherwise stick in the barrel. Bronze is still widely used today for springs, bearings, bushings and similar roles, and is particularly common in the bearings on small electric motors. Phosphor bronze is particularly suited to precision-grade bearings and springs. Bronze is typically 60% copper and 40% tin. Alpha bronze consists of the alpha solid solution of tin in copper. Alpha bronze alloys of 4-5% tin are used to make coins, springs, turbines and blades.

See also


- brass, a subset of the copper alloys in which zinc is the principal additive
- gunmetal
- cupronickel, an alloy used on ships
- lost-wax casting
- aluminum bronze

External links


- [http://www.jepsculpture.com/bronze.html Flash animation of lost-wax casting]
- [http://www.modernsculpture.com/bronze.htm Bronze Casting process explained - good pictures] Category:Copper alloys Category:Art materials ko:청동 ja:青銅

Cyprus

:See also Cypress (a common misspelling) for other meanings. The Republic of Cyprus (Greek: Κύπρος, Kýpros; Turkish: Kıbrıs; see also List of traditional Greek place names) is an island nation in the eastern Mediterranean Sea, 113 kilometres (70 miles) south of Turkey and around 120 km west of the Syrian coast.

Terminology

The name Cyprus has a somewhat uncertain etymology. One suggestion is that it comes from the Greek word "κυπάρισσος (kypa'rissos)" meaning "cypress tree" or even from the Greek name of the plant Lawsonia alba (henna), "κύπρος (kypros)". Another school suggests that it stems from the eterocyprian word for copper. Dossin, for example, suggests that it has roots to the Sumerian word for copper, "zubar" or even the word "kubar" (bronze), due to the large deposits of copper ore found on the island. Through overseas trade, the island has already given its name to the Classical Latin word for the metal, which appears in the phrase aes Cyprium , "metal of Cyprus", later shortened to cuprum. From there the word passed into European languages as "copper" in the English language, "cuivre" in French, "Kupfer" in German and "cobre" in Portuguese and in Spanish. Another probable suggestion is that it was named after the Greek goddess Aphrodite which was also called "Κυπρίς (kipris)". Note that Cyprus was the mythical birthplace of Aphrodite. Homer in his epics Iliad and Odyssey refers to the island of "Kύπρον (kypron)": “Μούσα μοι έννεπε έργα πολυχρύσου Αφροδίτης Κύπριδος” – “Muse sing to me the works of golden haired Aphrodite Cypridos”. It is also characteristic that in ancient times the name "Κύπρος (Cyprus)" in Greek was the first or second synthetic of names, such as: Αριστόκυπρος, Φιλόκυπρος, Κυπράνορας, Κυπροθέμης.

History

:Main article: History of Cyprus

Prehistoric and Ancient Cyprus

:Main article: Cyprus (Prehistory), Ancient history of Cyprus There are but scanty traces of the Stone Age, but the Bronze Age is characterized by a well-developed and clearly marked civilization. The people quickly learned to work the rich copper mines of the island. The Mycenæan civilization seems to have reached Cyprus at around 1600 B.C. and several Greek and Phœnician settlements that belong to the Iron Age can be found on the island. Cyprus was invaded by Thothmes III of Egypt about 1500 B.C., and was forced to pay tribute. Around 1200 B.C. begins the massive arrival of the Mycenæan Greeks as permanent settlers to Cyprus, a process which lasted for more than a century. This migration is remembered in many sagas concerning how some of the Greek heroes that participated in the Trojan war came to settle in Cyprus. The newcomers brought with them their language, their advanced technology and introduced a new outlook for visual arts. Thus from 1220 B.C. Cyprus has remained predominantly Greek in culture, language and population despite various influences resulting from successive conquests. In times Cyprus supplied the rest of the Greeks with timber for their fleets. In the 16th century B.C., Amasis of Egypt conquered Cyprus, which soon fell under the rule of the Persians when Cambyses conquered Egypt. In the Persian Empire, Cyprus formed part of the fifth satrapy and in addition to tribute it had to supply the Persians with ships and crews. In their new fate the Greeks of Cyprus had as companions the Greeks of Ionia (west coast of Anatolia) with whom they forged closer ties. When the Ionian Greeks revolted against Persia (499 BC) the Cypriots except for the city of Amathus, joined in at the instigation of Onesilos, brother of the king of Salamis, whom he dethroned for not wanting to fight for independence. The Persians reacted quickly sending a considerable force against Onesilos. The Persians finally won despite Ionian help. After their defeat, the Greeks mounted various expeditions in order to liberate Cyprus from the Persian yoke, but all their efforts bore only temporary results. Alexander the Great (356-323 B.C.) finally liberated the island from the Persians. Later, the Greek rulers of Egypt controlled it; finally Rome annexed it in 58-57 BC. No doubt the most important event that occurred in Roman Cyprus was the visit by Apostles Paul and Barnabas accompanied by St Mark who came to the island at the outset of their first missionary journey in 45 AD. After their arrival at Salamis they proceeded to Paphos where they converted the Roman Governor Sergius Paulus to Christianity. In this way Cyprus became the first country in the world to be governed by a Christian ruler.

Cyprus in ancient myth

Christianity Cyprus is the legendary birthplace of the goddess of beauty, love, sex and passion, the beautiful Aphrodite. According to Hesiod's Theogony, the goddess, who was also known as Kypris or the Cyprian, emerged fully grown from the sea where the severed genitals of the god Uranus were cast by his son, Kronos, causing the sea to foam (Greek: Aphros). The legendary site of Aphrodite's birth from the foam is at 'Petra tou Romiou' ('Aphrodite's Rock'), a large stack in the sea close to the coastal cliffs near Paphos. Throughout ancient history, Cyprus was a flourishing centre for the cultic worship of Aphrodite. Her birth was famously depicted by the artist Botticelli in The Birth of Venus.

Post-Classical and Modern Cyprus

Cyprus became part of the Byzantine Empire after the partitioning of the Roman Empire in 395, and remained so for almost 900 years. The Arabs pillaged the island in 646. In 654 a second, devastating Arab invasion took place. The island negotiated a relatively secure independence, but paid tribute to the Ummayads. After the rule of an independent Emperor (Isaac Comnenus), King Richard I of England captured the island in 1191 during the Crusades. Guy of Lusignan purchased the island from Richard in 1192. The Republic of Venice took control in 1489 after the death of the last Lusignan Queen, after which the Ottoman Empire conquered the Island in 1570. Cyprus was placed under British control on 4 June 1878 as a result of the Cyprus Convention, which granted control of the island to Britain in return for British support of the Ottoman Empire in the Russian-Turkish War. Famagusta harbour was completed in June 1906; by this time the island was a strategic naval outpost for the British Empire, shoring up influence over the Eastern Mediterranean and Suez Canal, the crucial main route to India. Cyprus was formally annexed by the United Kingdom in 1913 in the run-up to the First World War. Many Cypriots, now British subjects, signed up to fight in the British Army, in this and in the Second World War. During the 1940s and 1950s, Cypriots began to demand union with Greece. The Greek community held referenda in support of annexation, while the British sought to quell any movement which could threaten their possession of the island. In 1955 the struggle erupted into guerrilla activity with the foundation of EOKA, and in the closing years of the 1950s the political and intercommunal atmosphere on the island became increasingly fraught. Independence was attained in 1960 after exhaustive negotiations between the United Kingdom, as the colonial power, and Greece and Turkey, the cultural 'motherlands' for the two communities on Cyprus. The constitution produced by the negotiations was a biding document allocating government posts and public offices by ethnic quota. The constitution did not promote a healthy relationship between the residents of the island. The first President was the Greek Cypriot leader Archbishop Makarios III, and his Vice President was the leading Turkish Cypriot politician Dr Fazıl Küçük.

Post-independence

Dr Fazıl Küçük :Main article: Cyprus dispute During the 1960s, Makarios and Küçük pursued a non-aligned foreign policy, cultivating good relations with the Britain, Greece and Turkey and taking a leading role in developing the Non-Aligned Movement. However, by 1974 dissatisfaction among right-wing elements in favour of the long-term goal of Enosis - union with Greece - precipitated a coup d'etat against Makarios which was sponsored by Greece and led by the Cypriot National Guard. The new regime replaced Makarios with Nikos Giorgiades Sampson as president, and Bishop Gennadios as head of the Cypriot Orthodox Church. Diplomacy failed to resolve the crisis. Turkey invaded Cyprus by sea and air on 20 July, 1974, asserting its right to protect the Turkish Cypriot minority. Talks in Geneva involving Greece, Turkey, the United Kingdom and the two Cypriot factions failed in mid-August, and the Turks subsequently moved to gain control of 37% of the island's territory. Upwards of 200,000 Cypriots were uprooted, with Greek Cypriots forced to flee from the Turkish-controlled north and Turkish Cypriots displaced from the south. Greece made no armed response to the superior Turkish force but bitterly suspended military participation in the NATO alliance. The tension continued after Makarios returned to the presidency on December 7, 1974. He accepted a bizonal bicommunal federation as the form of a future state, but rejected any solution "involving transfer of populations and amounting to partition of Cyprus." The events of the summer of 1974 have dominated Cypriot politics ever since and have been a major point of contention between Greece and Turkey. After 1974 there were near-continual efforts to negotiate a settlement, which met with varying levels of hostility from either side. Turkish Cypriots proclaimed a separate state under Rauf Denktash on November 15, 1983, naming it the “Turkish Republic of Northern Cyprus.” The UN Security Council, in its Resolution 541 of November 18, 1983, declared the action illegal and called for withdrawal. Turkey is to date the only country to recognise the government of northern Cyprus. Conversely, it continues to reject calls to recognise the Republic of Cyprus as the sole legitimate government of Cyprus, and this political point has caused strained relations with the European Union. Relations in the eastern Mediterranean were particularly frayed in the mid-1990s, especially after the acquisition by the Cypriot government of Russian missiles in 1997 which were capable of reaching the Turkish coast. The S-300 missiles, in fact, never arrived in Cyprus but stayed on the neighbouring island of Crete. In April 2005, Turkish Cypriots elected Mehmet Ali Talat as their leader to succeed the retiring long-time leader Rauf Denktash, who staunchly opposed reunification. In contrast, Talat has been a keen supporter of reunification and subsequently the recently proposed "Annan Plan".

Geography

Mehmet Ali Talat :Main article: Geography of Cyprus Cyprus is geographically close to the Middle East (see also Southwest Asia and Near East) and due to the island's geographic proximity is often included in the region, though politically and culturally it is closely aligned with Europe, in particular Greece and to a lesser extent Turkey. Historically, Cyprus has been at the crossroads between Europe, Southwest Asia, and North Africa, with lengthy periods of mainly Greek and intermittent Levantine, Anatolian and British influences. The central plain (Mesaoria) with the Kyrenia and Pentadactylos mountains to the north and the Troodos mountain range to the south and west. There are also scattered but significant plains along the southern coast. The climate is temperate and Mediterranean with hot, dry summers and cool, variably rainy winters. The capital city, Nicosia, is located to the north-east of the centre of the island. All the other major cities are situated on the coast: Paphos to the south-west, Limassol to the south, Larnaca to the south-east, Famagusta to the east and Kyrenia to the north. See also:
- List of cities in Cyprus, Greek and Turkish names

Politics

:Main article: Politics of Cyprus After independence Cyprus became a founding member of the Non-Aligned Movement despite all three guarantor powers (Greece, Turkey and the UK) being NATO members. Cyprus left the Non-Aligned Movement in 2004 to join the EU. The 1960 Cypriot Constitution provided for a presidential system of government with independent executive, legislative, and judicial branches, as well as a complex system of checks and balances, including a weighted power-sharing ratio designed to protect the interests of the Turkish Cypriots. The executive, for example, was headed by a Greek Cypriot president, Archbishop Makarios III, and a Turkish Cypriot vice president, Dr Fazıl Küçük, elected by their respective communities for 5-year terms and each possessing a right of veto over certain types of legislation and executive decisions. The House of Representatives was elected on the basis of separate voters' rolls. Since 1964, following clashes between the two communities, the Turkish seats in the House have been vacant after their withdrawal from the government, and the Greek Cypriot Communal Chamber was abolished. The responsibilities of the chamber were transferred to the newfounded Ministry of Education. By 1967, when a military junta had seized power in Greece, the political impetus for enosis had faded, partly as a result of the non-aligned foreign policy of Cypriot President Makarios. Enosis remained an ideological goal, despite being pushed significantly further down the political agenda. Dissatisfaction in Greece with Makarios's perceived failure to deliver on earlier promises of enosis convinced the Greek colonels to sponsor the 1974 coup in Nicosia. Turkey responded by invading Cyprus in a move not approved by the other two international guarantor powers, Greece and the United Kingdom. Turkey did not use its authority as a guarantor to restore the status quo before the coup. Claiming to be responding to an imminent threat to the Republic of Cyprus and the need to protect the Turkish minority in Cyprus from attacks by Greek militias, it captured the northern third of the island, causing 180,000 Greek Cypriots to flee to the south. 55,000 Turkish Cypriots subsequently relocated from the south to the north (see Cyprus dispute). Many thousands of others, from both sides, left the island entirely. Subseqently, the Turkish Cypriots established their own seperatist institutions with a popularly elected de facto President and a Prime Minister responsible to the National Assembly exercising joint executive powers. In 1983, the Turkish Cypriots declared an independent "Turkish Republic of Northern Cyprus" (TRNC), an action opposed by the United Nations Security Council. In 1985, the TRNC adopted a constitution and held its first elections. See also:
- Turkish Republic of Northern Cyprus
- Foreign relations of Cyprus
- List of political parties in Cyprus
- Military of Cyprus

Political division

Cyprus gained independence from the United Kingdom in 1960, with the UK, Greece and Turkey retaining limited rights to intervene in internal affairs. Since 1974, Cyprus has been divided, de facto, into the Greek-Cypriot controlled southern two-thirds of the island and the Turkish-occupied northern one-third. The Republic of Cyprus is the internationally recognised government of Cyprus, which controls the southern two-thirds of the island. Turkey aside, all foreign governments and the United Nations recognise the sovereignty of the Republic of Cyprus over the whole island of Cyprus. United Nations The Turkish Cypriot administration of the northern part of the island, together with Turkey, does not accept the Republic's rule over the whole island and refer to it as the "Greek Authority of Southern Cyprus". Its territory, the status of which remains disputed, extends over the northern third of the island. The north proclaimed its independence in 1975, and the self-styled Turkish Republic of Northern Cyprus was established in 1983. This state was recognised only by Turkey. The Organization of the Islamic Conference granted it observer member status under the name of "Turkish Cypriot State". The other power with territory on Cyprus is the United Kingdom. Under the independence agreement, the UK retained title to two areas on the southern coast of the island, around Akrotiri and Dhekelia, known collectively as the UK sovereign base areas. They are used as military bases.

Exclaves and enclaves

Cyprus has four exclaves, all in territory that belongs to the British Sovereign Base Area of Dhekelia. The first two are the villages of Ormidhia and Xylotimbou. Additionally there is the Dhekelia Power Station, which is divided by a British road into two parts. The northern part is an enclave like the two villages, whereas the southern part is located by the sea and therefore not an enclave —although it has no territorial waters of its own [http://geosite.jankrogh.com/cyprus.htm]. The United Nations (UN) buffer zone separating the territory controlled by the Turkish Cypriot administration from the rest of Cyprus runs up against Dhekelia and picks up again from its east side, off of Ayios Nikolaos (connected to the rest of Dhekelia by a thin land corridor). In that sense, the buffer zone turns the south-east corner of the island, the Paralimni area, into a de facto, though not de jure, exclave.

Reunification, the Annan Plan and EU entry

The results of early negotiations between the Greek and Turkish sides resulted in a broad agreement in principle to reunification as a bi-cameral, bi-zonal federation with territory allocated to the Greek and Turkish communities within a united island. However, agreement was never reached on the finer details, and the two sides often met deadlock over the following points, among others: The Turkish side:
- favoured a weak central government presiding over two sovereign states in voluntary assocation, a legacy of earlier fears of domination by the majority Greek Cypriots; and
- opposed plans for demilitarisation, citing security concerns. The Greek side:
- took a strong line on the right of return for refugees to properties vacated in the 1974 displacement of Cypriots on both sides;
- took a dim view of any proposals which did not allow for the repatriation of Turkish settlers from the mainland who had emigrated to Cyprus since 1974; and
- supported a stronger central government. The continued difficulties in finding a settlement presented a potential obstacle to Cypriot entry to the European Union, for which the government had applied in 1997. UN-sponsored talks between the Greek and Turkish leaders, Glafkos Klerides and Rauf Denktash, continued intensively in 2002, but without resolution. In December 2002 the EU formally invited Cyprus to join in 2004, insisting that EU membership would apply to the whole island and hoping that it would provide a significant enticement for reunification resulting from the outcome of ongoing talks. However, weeks before the UN deadline, Klerides was defeated in presidential elections by right-wing candidate Tassos Papadopoulos. Papadopoulos had a reputation as a hard-liner on reunification and had rejected previous UN attempts to reunify the island. By mid-March, the UN declared that the talks had failed. A United Nations plan sponsored by Secretary-General Kofi Annan was announced on 31 March 2004, based on what progress had been made during the talks in Switzerland and fleshed out by the UN, was put to both sides in separate referenda on 24 April 2004. The Greek side overwhelmingly rejected the Annan Plan, and the Turkish side voted in favour. In May 2004, Cyprus entered the EU, although in practice membership only applies to the southern part of the island. In acknowledgement of the Turkish Cypriot community's support for reunification, however, the EU made it clear that trade concessions would be reached to stimulate economic growth in the north, and remains committed to reunification under acceptable terms. See also:
- Annan Plan
- 2004 referendum
- Cyprus dispute
- UN Buffer Zone on Cyprus.

Economy

:Main article: Economy of Cyprus Economic affairs in Cyprus are dominated by the division of the country into the southern (Greek) area controlled by the Cyprus Government and the northern Turkish Cypriot-administered area. The Greek Cypriot economy is prosperous but highly susceptible to external shocks. Erratic growth rates in the 1990s reflect the economy's vulnerability to swings in tourist arrivals, caused by political instability on the island and fluctuations in economic conditions in Western Europe. Economic policy in the south in the years leading up to 2005 focused on meeting the criteria for admission to the European Union. As in the Turkish sector, water shortage is a growing problem, and several desalination plants are planned. Recently, oil has been discovered in the sea South of Cyprus (between Cyprus and Egypt) and talks are under way with Egypt to reach an agreement as to the exploitation of these resources. The level of the oil field in terms of production (barrels per day) that the two countries will be able to produce is still a matter of speculation. The Turkish Cypriot economy has about one-fifth the population and one-third the per capita GDP of the south. Because it is recognised only by Turkey, it has had much difficulty arranging foreign financing, and foreign firms have hesitated to invest there. The economy remains heavily dependent on agriculture and government service, which together employ about half of the work force. Moreover, the small, vulnerable economy has suffered because the Turkish lira is legal tender. To compensate for the economy's weakness, Turkey provides direct and indirect aid to tourism, education, industry, etc. Eventual adoption of the euro currency is required of all new countries joining the European Union, and the Cyprus government currently intends to adopt the currency on 1 January 2008.

Demographics

:Main article: Demographics of Cyprus Greek and Turkish Cypriots share many customs but maintain their ethnicity based on religion, language, and close ties with their respective motherlands. The major part of Greek Cypriots are Eastern Orthodox Christians, whereas Turkish Cypriots are Muslims. Greek is the predominant language in the south, Turkish in the north. This delineation is only reflective of the post-1974 division of the island, which involved an expulsion of Greek Cypriots from the north and the analoguous move of Turkish Cypriots from the south. Historically however, Greek and Turkish (the Cypriot dialects) were largely evenly distributed throughout the island, although Greek-speakers were in a substantial majority (82%). English is widely understood, and is taught in schools from primary age.

Education

Cyprus has a well-developed system of primary and secondary education offering both public and private education. Unlike in other countries, state schools are generally seen as equivalent or better in quality of education than private sector institutions. The majority of Cypriots receive their higher education at Greek, British, Turkish, EU & US universities, while there are also sizeable emigrant communities in the United Kingdom and Australia. Private colleges and state-supported universities have been developed by both the Turkish and Greek communities. According to the 1960 constitution, education is under the control of the two communities (the communal chambers). State education was based on nationalisation of existing community supported schools from the colonial period. Thus following 1974 the Cypriot system follows the Greek system in the south, in other words providing their students with an apolytirion, and the Turkish system in the north. A large number of students after sitting for A-levels and/or SATs study abroad, mainly in English speaking countries such as the US or UK, but also in other European destinations such as France and Germany. Traditionally the left wing party AKEL provided scholarships for its members to study in Eastern Europe. Eastern European countries, especially Bulgaria and Hungary, are still popular destinations for students .
- [http://www.ucy.ac.cy University of Cyprus]
- [http://www.tucy.ac.cy Technical University of Cyprus]
- [http://www.mlsi.gov.cy/mlsi/hti/hti.nsf/dmlindex_en/dmlindex_en?OpenDocument Higher Technical Institute] (taught in English) situated in Nicosia
- [http://www.cycollege.ac.cy Cyprus College] (taught in English) situated in Nicosia
- [http://www.intercollege.ac.cy/ Intercollege] (taught in English) situated in Nicosia and Larnaca
- [http://www.fit.ac.cy/ The Frederick institute] (taught in English) situated in Nicosia and Limassol
- [http://www.philips.ac.cy/ Philips College] (taught in English/Greek) situated in Nicosia
- [http://www.ac.ac.cy/ Americanos College] (taught in English/Greek) situated in Nicosia Also on the Turkish Side:
- [http://www.emu.edu.tr/ Eastern Mediterranean University ] (taught in English) in Famagusta (Gazi Magosa)
- [http://www.gau.edu.tr/ Girne American University ] (taught in English) in Kyrenia
- [http://www.neu.edu.tr/ Near East University ] (taught in English) in Nicosia
- [http://www.ciu.edu.tr/ International Cyprus University ] (taught in English) in Nicosia
- [http://www.lefke.edu.tr/ European University of Lefke] (taught in English) in Lefka
- [http://ncc.metu.edu.tr/ Middle East Technical University Northern Cyprus Campus ] (taught in English) in Kalkanli

Miscellaneous


- Communications in Cyprus
- Holidays in Cyprus
- List of Cypriots
- Military of Cyprus
- Music of Cyprus
- Alexander the Great
- Transportation in Cyprus
- Districts of Cyprus

External links

Government
- [http://www.cyprus.gov.cy/ Republic of Cyprus]
- [http://www.moi.gov.cy/moi/pio/pio.nsf/index_en/index_en?opendocument# Press and Information Office]
- [http://www.cyprus.gov.cy/cyphome/govhome.nsf/0/AC8717AD3CF09FC1C2256FC8003AFBD8?OpenDocument&languageNo=1 Religious Groups in Cyprus]
- [http://www.mof.gov.cy/mof/cystat/statistics.nsf/index_en/index_en?OpenDocument Statistical Service of the Republic of Cyprus] General information
- [http://www.cia.gov/cia/publications/factbook/geos/cy.html CIA World Factbook - Cyprus]
- [http://www.state.gov/p/eur/ci/cy/ US State Department - Cyprus] includes Background Notes, Country Study and major reports
- [http://dmoz.org/Regional/Middle_East/Cyprus/ Open Directory Project - Cyprus] directory category
- [http://cyprus.angloinfo.com/ AngloINFO Cyprus - information in English]
- [http://www.ikypros.com/ Portal about villages in Greek]
- [http://www.worldwide-tax.com/cyprus/indexcyprus.asp Cyprus taxes, business and economy].
- [http://www.phigita.net/ Cyprus Blogs & News]
- [http://www.cyprus-hotelguide.com/ Cyprus Hotel and Travel Guide ]
- [http://www.willgoto.com/246/1/categories.aspx Travel guide to Cyprus] Category:Middle Eastern countries Category:Southwest Asian countries Category:European Union member states Category:Bicontinental countries Category:Phoenician colonies Category:Hellenistic colonies zh-min-nan:Kypros ko:키프로스 ms:Cyprus ja:キプロス simple:Cyprus th:ประเทศไซปรัส fiu-vro:Küprüs

Smelting

:See smelt for the style of fishing with dip nets in tributaries of the Great Lakes during the spring spawning run of that small fish. Chemical reduction, or smelting, is a form of extractive metallurgy. The main use of smelting is to produce iron and steel from iron ore. Smelting is also used to extract copper and other base metals from their raw ores. It makes use of a chemical reducing agent such as carbon (coke, or in earlier times charcoal) to change the oxidation state of the metal ore. When coke is mixed with iron ore and heated, the oxygen will move from the iron to the carbon. The iron will be reduced, and the carbon will be oxidised, producing carbon dioxide and carbon monoxide. A fluxing agent such as limestone is used to remove the accompanying rock gangue as slag (also called scoria or cinder). In Ancient Egypt somewhere between the Third Intermediate Period and 23rd Dynasty (1100 BC - 750 BC) there are indications of iron working. There are further indications of iron smelting and working in West Africa in 500 BC [http://www.louisville.edu/a-s/history/herlin/textsup.htm]. The process of smelting became widely used during the Industrial Revolution, when it was used extensively in the production of iron and steel.

See also


- Blast furnace
- Furnace
- Metallurgy
- Pyrometallurgy
- Iron Age Category:Metallurgy Category:Metals processes ja:製錬

Malachite

:This article is about the mineral. For the butterfly see Malachite (butterfly) Malachite (butterfly)] Malachite is a carbonate mineral, copper(II) carbonate hydroxide Cu2CO3(OH)2. Malachite has a hardness between 3.5 and 4. It crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagtitic masses. Malachite often results from weathering of copper ores and is often found together with azurite (Cu3(CO3)2(OH)2), goethite, and calcite. Except for the iridescent green colour, the properties of malachite are very similar to those of azurite and aggregates of the two minerals together are frequently found, although malachite is more common than azurite. Typically associated with copper deposits associated with limestones, the source of the carbonate. It was used as a mineral pigment in green paints from antiquity until about 1800. The pigment is moderately lightfast, very sensitive to acids and varying in colour. The natural form was being replaced by its synthetic form, verditer amongst other synthetic greens. It is also used for decorative purposes, such as in the Malachite Room in the Hermitage which features a huge malachite vase. Large quantities of malachite have been mined in the Urals. It is found in the Democratic Republic of Congo; Tsumeb, Namibia; Ural mountains, Russia; Mexico; Broken Hill, New South Wales; England; Lyon; and in the Southwestern United States especially in Arizona at Bisbee and Morenci.

References


- Hurlbut, Cornelius S.; Klein, Cornelis, 1985, Manual of Mineralogy, 20th ed., John Wiley and Sons, New York ISBN 0471805807
- [http://mineral.galleries.com/minerals/carbonat/malachit/malachit.htm Mineral Galleries]
- [http://www.hermitagemuseum.org/html_En/08/hm88_0_1_62.html Virtual tour of the Malachite Room] Category:Carbonate minerals

Azurite

Azurite is a carbonate mineral with chemical composition Cu3(CO3)2(OH)2, (copper carbonate hydroxide). Azurite is often found in association with the green mineral malachite as a result of the weathering and oxidation of copper sulfide minerals. The name azurite comes from the Arabic word for blue. Azurite is used in jewelry and also collected as a beautiful mineral specimen.

Use as a pigment

Azurite has been used as a blue mineral pigment for centuries. It was formerly known as Azurro Della Magna (from Italian). When mixed with oil it turns slightly green. When mixed with egg yolk it turns green-grey. It is also known by the names Blue Bice and Blue Verditer.

See also


- list of minerals Category:Carbonate minerals Category:Pigments

Gold

Gold is a chemical element in the periodic table that has the symbol Au (L. aurum) and atomic number 79. A soft, shiny, yellow, dense, malleable, ductile (trivalent and univalent) transition metal, gold does not react with most chemicals but is attacked by chlorine, fluorine and aqua regia. The metal occurs as nuggets or grains in rocks and in alluvial deposits and is one of the coinage metals. For millennia, gold has served as money and is also used in jewelry, dentistry, and in electronics. Gold forms the basis for a monetary standard used by the International Monetary Fund (IMF) and the Bank for International Settlements (BIS). Its ISO currency code is XAU.

Notable characteristics

Gold is a metallic element with a characteristic yellow color, but can also be black or ruby when finely divided, while colloidal solutions are intensely colored and often purple. These colors are the result of gold's plasmon frequency lying in the visible range (due to a relativistic effect), which causes red and yellow light to be reflected, and blue light to be absorbed. It is one of only three metals which have an actual easily-identifiable color; the other two are copper, which is red, and caesium, which has a pale golden color. It is the most malleable and ductile metal known; a single gram can be beaten into a sheet of one square meter, or an ounce into 300 square feet. A soft metal, gold will readily form alloys with many other metals. This can be done to increase its strength, or create several exotic colors, sold for instance in the western United States to the tourist trade as "Black Hills" gold. Adding copper yields a redder metal, iron blue, Silver produces green, aluminium purple, platinum metals white, and natural bismuth together with silver alloys produce black. Native gold contains usually eight to ten per cent silver, but often much more — alloys with a silver content over 20% are called electrum. As the amount of silver increases, the color becomes whiter and the specific gravity lower. Gold is a good conductor of heat and electricity, and is not affected by air and most reagents. Heat, moisture, oxygen, and most corrosive agents have very little chemical effect on gold, making it well-suited for use in coins and jewelry; conversely, halogens will chemically alter gold, and aqua regia dissolves it. Common oxidation states 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 out as gold metal by the addition of virtually any other metal as the reducing agent. The added metal is oxidized and dissolves allowing the gold to be displaced from solution and be recovered as a solid precipitate. Recent research undertaken by Frank Reith of the Australian National University shows that microbes play an important role in the formation of gold deposits, transporting and precipitating gold to form grains and nuggets that collect in alluvial deposits. [http://www.abc.net.au/science/news/enviro/EnviroRepublish_1032376.htm]

Applications

Pure gold is too soft for ordinary use and is hardened by alloying with silver, copper, and other metals. Gold and its many alloys are most often used in jewelry, coinage and as a standard for monetary exchange in many countries. Because of its high electrical conductivity and resistance to corrosion and other desirable combinations of physical and chemical properties, gold also emerged in the late 20th century as an essential industrial metal.
- Gold can be made into thread and used in embroidery.
- Gold performs critical functions in computers, communications equipment, spacecraft, jet aircraft engines, and a host of other products.
- The resistance to oxidation of gold has led to its widespread use as thin layers electroplated on the surface of electrical connectors to ensure a good connection.
- Gold is used in restorative dentistry especially in tooth restorations such as crowns and bridges.
- Colloidal gold (a gold nanoparticle) is an intensely colored solution that is currently studied in many labs for medical, biological and other applications. It is also the form used as gold paint on ceramics prior to firing.
- Chlorauric acid is used in photography for toning the silver image.
- Gold(III) chloride is used as a catalyst in organic chemistry. It is also the usual starting point for making other gold compounds.
- Disodium aurothiomalate is a treatment for rheumatoid arthritis (administered intramuscularly). It inhibits lymphocyte proliferation, lysosomal enzyme release, the release of reactive oxygen species from macrophages, and IL-1 production. However, it can also cause photosensitive rashes, gastrointestinal disturbance, and kidney damage.
- The gold isotope Au-198, (half-life: 2.7 days) is used in some cancer treatments and for treating other diseases.
- Gold is used as a coating enabling biological material to be viewed under a scanning electron microscope.
- Many competitions and honors, such as the Olympics and the Nobel Prize, award a gold medal to the winner (with silver to the second-place finisher, and bronze to the third.)
- Since it is a good reflector of both infrared and visible light, it is used for the protective coatings on many artificial satellites.
- Gold flake is used on and in some gourmet sweets and drinks. Having no reactivity it adds no taste but is taken as a delicacy.
- White gold (an alloy of gold with platinum, palladium, nickel, and/or zinc) serves as a substitute for platinum.
- Green gold (a gold/silver alloy) is used in specialized jewelry while gold alloys with copper (reddish color) are more widely used for that purpose (rose gold).

History

rose gold Gold (Sanskrit jval, Greek χρυσος [khrusos], Latin aurum for "shining dawn", Anglo-Saxon gold, Chinese 金 [jīn]) has been known and highly valued since prehistoric times. It may have been the first metal used by humans and was valued for ornamentation and rituals. Egyptian hieroglyphs from as early as 2600 BC describe gold, which king Tushratta of the Mitanni claimed was as "common as dust" in Egypt. Egypt and Nubia had the resources to make them major gold-producing areas for much of history. Gold is also mentioned several times in the Old Testament. The south-east corner of the Black Sea was famed for its gold. Exploitation is said to date from the time of Midas, and this gold was important in the establishment of what is probably the world's earliest coinage in Lydia between 643 and 630 BC. 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 Central America, Peru, and Colombia. Gold has long been considered one of the most precious metals, and its value has been used as the standard for many currencies (known as the gold standard) in history. Gold has been used as a symbol for purity, value, royalty, and particularly roles that combine these properties (see gold album). Gold in antiquity was relatively easy to obtain geologically; however, 75% of all gold ever produced has been extracted since 1910.[http://www.goldsheetlinks.com/production2.htm] It has been estimated that all the gold in the world that has ever been refined would form a single cube 20 m (66 ft) a side. The primary goal of the alchemists was to produce gold from other substances, such as lead — presumably by the interaction with a mythical substance called the philosopher's stone. Although they never succeeded in this attempt, the alchemists promoted an interest in what can be done with substances, and this laid a foundation for today's chemistry. Their symbol for gold was the circle with a point at its center (☉), which was also the astrological symbol, the Egyptian hieroglyph and the ancient Chinese character for the Sun (now 日). For modern attempts to produce artificial gold, see gold synthesis. During the 19th century gold rushes occurred whenever large gold deposits were discovered, including the California, Colorado, Otago, Australia, Witwatersrand, Black Hills, and Klondike gold rushes. Because of its historically high value, much of the gold mined throughout history is still in circulation in one form or another.

Value

Klondike] Klondike Like other precious metals, gold is measured by troy weight and by grams. When it is alloyed with other metals the term carat or karat is used to indicate the amount of gold present, with 24 carats being pure gold and lower ratings proportionally less. The purity of a gold bar can also be expressed as a decimal figure ranging from 0 to 1, known as the millesimal fineness, such as 0.995. The price of gold is determined on the open market, but a procedure known as the Gold Fixing in London, originating in 1919, provides a twice-daily benchmark figure to the industry. Historically gold was used to back currency in an economic system known as the gold standard in which one unit of currency was equivalent to a certain weight of gold. As part of this system, governments and central banks attempted to control the price of gold by setting values at which they would exchange it for currency. For a long period the United States government set the price of gold at $20.67 per troy ounce ($664.56/kg) but in 1934 the price of gold was set at $35.00 per troy ounce ($1125.27/kg). By 1961 it was becoming hard to maintain this price, and a pool of US and European banks began to act together to defend the price against market forces. On March 17 1968, economic circumstances caused the collapse of the gold pool, and a two-tiered pricing scheme was established whereby gold was still used to settle international accounts at the old $35.00 per troy ounce ($1.13/g) but the price of gold on the private market was allowed to fluctuate; this two-tiered pricing system was abandoned in 1975 when the price of gold was left to find its free-market level. Central banks still hold historical gold reserves as a reserve asset although the level has generally been declining. The largest gold depository in the world is that of the U.S. Federal Reserve Bank, held at Fort Knox. Since 1968 the price of gold on the open market has ranged widely, with a record high of $850/oz ($27,300/kg) on 21 January 1980, to a low of $252.90/oz ($8,131/kg) on 21 June 1999 (London Fixing). Prices have risen to the $500/oz mark in late 2005, due to a depreciation of the US dollar and inflation due to rising energy costs.

Gold and the money supply

In January 1959 US M3 money supply was $288.8 billion, and the Official Gold Holdings of the United States was then 17,335.1 Tonnes, or about 557 million ounces (there are 32,150.7 Troy Ounces in a Tonne). That means that in 1959, there were $518 in circulation for every ounce of gold reserves held by the USA. Although the theoretical price should then have been $518 per ounce, the actual price, as fixed under the gold standard was only $35 an ounce. By August 2005, the US M3 money supply had risen to $9,873.9 billion, whilst at the same time the Official Gold Holdings of the United States had fallen to just 8,133.5 Tonnes, or about 261 million Troy Ounces. This means that today, in 2005, there are $37,831 in circulation for every ounce of gold held by the United States. The above numbers show the falling influence of gold in the monetary system of the world today. Goldbugs believe, or even hope, that one day gold's importance will return as the printing of paper money gets out of control and we end in a hyper-inflationary fiat money collapse.

Restrictions on gold ownership

Because of its use as a reserve store of value, the possession of gold is sometimes restricted or banned. Within the United States, the private possession of gold except as jewelry and coin collecting was banned between 1933 and 1975. President Franklin D. Roosevelt confiscated gold by [http://www.the-privateer.com/1933-gold-confiscation.html Executive Order 6102], and President Richard Nixon closed the gold window by which foreign countries could exchange American dollars for gold at a fixed rate.

Return of a Gold Standard?

In the first few years of the 21st century, reports started to circulate that Malaysia was planning a return to the gold standard -- to issue and use gold dinars as currency in international trade. The purported purpose of this move would be to reduce dependence on the United States dollar as a reserve currency, and to establish a non-debt-backed currency in accord with Islamic law against the charging of interest. [http://www.islamidag.dk/ulamaongold.html] Nonetheless, gold dinar currency has not yet emerged. [http://english.aljazeera.net/NR/exeres/E7515CEE-880E-492F-B225-A94E21D90D2B.htm] [http://www.mineweb.net/columns/american_notes/336075.htm]

Gold in investment portfolios

As a tangible investment gold is sometimes held as part of a portfolio because over the long term gold has an extensive history of maintaining its value. It has in the last century gained ground in relation to fiat currencies owing to inflation. Gold becomes particularly desirable in times of extremely weak confidence and during hyperinflation because gold maintains its value even as fiat money becomes worthless. People who enjoy investing in gold are known as goldbugs. Futures contracts based on gold currently trade on various exchanges around the world. In the US this occurs primarily on COMEX (Commodity Exchange) which is a subsidiary of the New York Mercantile Exchange. Speculation about the future price of gold and other commodities is carried on at COMEX. Recently, gold-based ETFs like [http://finance.yahoo.com/q?s=GLD GLD] have emerged as a more convenient investment vehicle. In some countries such as Switzerland, it is possible to hold physical gold as part of an investment portfolio, due to the absence of taxes and narrow bid-ask spreads, however in other countries portfolio managers sometimes hold gold shares or gold bullion securities as a proxy for the metal itself. Exchange Traded Funds such as Gold Bullion Securities are securities sponsored by the World Gold Council and which are fully backed up by allocated gold held by a custodian. The main Gold Bullion Securities are as follows:
- New York Stock Exchange (NYSE), Symbol:GLD (Streettracks Gold Shares, ISIN No. US8633071043)
- London Stock Exchange (LSE) Symbol GBS (Gold Bullion Securities ISIN No. GB00B00FHZ82)
- Euronext France Symbol:GBS (Gold Bullion Securities ISIN No. GB00B00FHZ82 )
- Australian Stock Exchange (ASX), Symbol:GOLD (Gold Bullion Securities ISIN No. AU00000GOLD7)
- Johannesburg Securities Exchange (JSE), Symbol:GLD (New Gold Debentures ISIN No. ZAE000060067 )

Occurrence

Exchange Traded Fund Due to its relative chemical inertness gold is usually found as the native metal or alloy. Occasionally large accumulations of native gold (also known as nuggets) occur but usually gold occurs as minute grains. These grains occur between mineral grain boundries or as inclusions within minerals. Common gold associations are quartz often as veins and sulfide minerals. The most common sulfide associations are pyrite, chalcopyrite, galena, sphalerite, arsenopyrite, stibnite and pyrrhotite. Rarer mineral associations are petzite, calaverite, sylvanite, muthmannite, nagyagite and krennerite. Gold is widely distributed in the Earth's crust at a background level of 0.03 g/1000 kg (0.03 ppm by weight). Hydrothermal ore deposits of gold occur in metamorphic rocks and igneous rocks; alluvial deposits and placer deposits originate from these sources. The primary source of gold is usually igneous rocks or surface concentrations. A deposit usually needs some form of secondary enrichment to form an economically viable ore deposit: either chemical or physical processes like erosion or solution or more generally metamorphism, which concentrates the gold in sulfide minerals or quartz. There are several primary deposit types, common ones are termed reef or vein. Primary deposits can be weathered and eroded, with most of the gold being transported into stream beds where it congregates with other heavy minerals to form placer deposits. In all these deposits the gold is in its native form. Another important ore type is in sedimentary black shale and limestone deposits containing finely disseminated gold and other platinum group metals. Gold occurs in sea water at 0.1 to 2 mg/t (0.1 to 2 ppb by weight) depending on sample location.

Production

ppb Economic gold extraction can be achieved from ore grades as little as 0.5 g/1000 kg (0.5 ppm) on average in large easily mined deposits, typical ore grades in open-pit mines are 1–5 g/1000 kg (1-5 ppm), ore grades in underground or hard rock mines are usually at least 3 g/1000 kg (3 ppm) on average. Ore grades of 30 g/1000 kg (30 ppm) are usually needed before gold is visible to the naked eye, therefore in most gold mines you will not see any gold. It is claimed, that all the gold that has been mined throughout the history of mankind could be incorporated in a solid ball with a diameter of 27 metres. metre Since the 1880s South Africa has been the source for a large proportion of the world's gold supply. Production in 1970 accounted for 79% of the world supply, producing about 1,000 tonnes, however production in 2004 was 342 tonnes. This decline was due to the increasing difficulty of extraction and changing economic factors effecting the industry in South Africa. The city of Johannesburg was built atop the world's greatest gold finds. Gold fields in the Orange Free State and the Transvaal are deep and require the world's deepest mines. The Second Boer War of 1899–1901 between the British Empire and the white Boers was at least partly over the rights of miners and possession of the gold wealth in South Africa. Other major producers are Canada, United States and Western Australia. Mines in South Dakota and Nevada supply two-thirds of gold used in the United States. Siberian regions of the USSR also used to be significant in the global gold mining industry. Kolar Gold Fields in India is another example of a city being built on the greatest gold deposits in India. In South America, the controversial project Pascua Lama aims at exploitation of rich fields in the high mountains of Atacama, at the border between Chile and Argentina. The idea of producing gold out of lesser metals or other cheap substances has fascinated people throughout the centuries. Scientists, kings and charlatans obsessed with the secret art of alchemy accidentally invented practically useful materials (e.g. porcelain), while searching in vain for the philosopher's s