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Gold [Au]
CAS-ID: 7440-57-5
An: 79 N: 118
Am: 196.96655 g/mol
Group No: 11
Group Name: Coinage metal
Block: d-block  Period: 6
State: solid at 298 K
Colour: gold (!) Classification: Metallic
Boiling Point: 3129K (2856°C)
Melting Point: 1337.33K (1064.18°C)
Density: 19.3g/cm3
Discovery Information
Who: Known to the ancients. Gold 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. Eqyptian hieroglyphs from as early as 2600BC mention gold. 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.
Name Origin
Gold from old English word geolo (yellow); Au from Latin: aurum (gold).
 "Gold" in different languages.
Sources
Found in veins in the crust, with copper ore and natively. Major producers include South Africa, Canada, the United States and Western Australia.
Around 1400 tons are produced each year.
Abundance
 Universe: 0.0006 ppm (by weight)
 Sun: 0.001 ppm (by weight)
 Carbonaceous meteorite: 0.17 ppm
 Earth's Crust: 0.011 ppm
 Seawater: 5 x 10-5 ppm
 Human:
   100 ppb by weight
   3 ppb by atoms
Uses
Pure gold is too soft for ordinary use and is hardened by alloying with silver, copper, and other metals. These alloys are mostly used in jewellery and coinage.
White gold (an alloy of gold with platinum, palladium, nickel, and/or zinc) serves as a substitute for solid platinum.
Gold is used in restorative dentistry especially in tooth restorations such as crowns and permanent bridges as its slight maliablity makes a superior molar mating surface to other teeth, unlike a harder ceramic crown.
History
Gold 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 "more plentiful than dirt" 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, and is included with the gifts of the magi in the first chapters of Matthew New 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.
Although the price of some platinum group metals can be much higher, gold has long been considered the most desirable of 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. Gold as a sign of wealth and prestige was made fun of by Thomas More in his treatise Utopia. On that imaginary island, gold is so abundant that it is used to make chains for slaves, tableware and lavatory-seats. When ambassadors from other countries arrive, dressed in ostentatious gold jewels and badges, the Utopians mistake them for menial servants, paying homage instead to the most modestly-dressed of their party.
During the 19th century, gold rushes occurred whenever large gold deposits were discovered. The first major gold strike in the United States occurred in a small north Georgia town called Dahlonega. Further gold rushes occurred in California, Colorado, Otago, Australia, Witwatersrand, Black Hills, and Klondike.
Because of its historically high value, much of the gold mined throughout history is still in circulation in one form or another.
Notes
On the 13th of March 2008 the price of gold reached $1000 per troy ounce (31.1035g) for the first time in history. This works out at $32150 per kilogram!
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.
Supposedly around half of the world's supply of gold is stored in the United States Treasury Department's gold depository in Fort Knox Kentucky, which is considered to be one of the most secure buildings in the world.
Because gold is traded like currencies, it has it's own ISO currency code, XAU (USD = US dollars, GBP = GB Pounds sterling etc.).
Gold in antiquity was relatively easy to obtain geologically; however, 75% of all gold ever produced has been extracted since 1910. 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) on a side (8000 m3).
At the end of 2001, it was estimated that all the gold ever mined totalled only 145,000 tonnes.
Images
Gold ore Gold ore
A Gold bar A Gold bar