Gold - Symbol Au from the latin word aurum, is a precious metal prized for it's deep yellow colour and lustre, it has been used since ancient times as a symbol of wealth and has been used for many years in coinage and currency. Gold is used in Jewellery, for investment as bullion, and also in industry as corrosion free electrical connectors in computers and phones etc. It is measured in Grams or in Troy Ounces - where a troy ounce is slightly heavier than a standard ounce (in fact 1 Troy ounce is equal to 1.09714286 normal ounces - and 1 Troy ounce is equal to 31.1034768 grams).
Gold in it's Raw State Gold in it's Raw State
Gold is also used in thread, as a colouring agent in glass, in protective coatings on Satellites, in heat shielding in high end automobiles and some aircraft cocpit windows where it appears transparent and used for de-icing purposes. Amazingly, gold is also used as a food decoration in the form of gold leaf where it can be eaten as pure gold is non-toxic and non-irritating when ingested. It is also a component of the alcoholic drinks "Goldschlager, Gold Strike and Goldwasser" and is approved as food additive E175.
Gold used for eating Gold Bars and Coins
Gold is one of the highest atomic numbered elements and thought to have been formed inside supernovae (Exploding stars) - and would have sunk to the earth's core. Therefore, most of the gold present is thought to have been delivered by the bombardment of asteroids about 4 billion years ago.
Because Gold is soft and will wear away slowly, it is often alloyed with other metals when used in coins and jewellery - such as copper, silver, palladium and other metals, and depending upon the metal used may also change the colour of the gold - for example alloying with Iron will give blue gold, aluminium will give purple, copper will give red etc. The ratio of gold to a corresponding mix of alloys will give the fineness of gold or purity and this is measured in Carats or Karats - where the symbol K or kt is used and is measured as K=24 Mg/Mm. Where K is the Carat Rating, Mg is the mass of pure gold and Mm is the total mass of the material.
Gold used in connectors in Computers Gold used in Audio connectors
Thus, 24 Carat Gold is 99.95% to 100%, 22 Carat is 91.66% to 95.83%, 18 Carat is 75% to 79.16%, 9 Carat is 37.5% Gold etc.
Although gold is soft and malleable, it is resistant to corrosion and most acids, only being dissolved in mercury, types of cyanide and aqua regia (Nitro-Hydrochloric Acid). The world consumption is about 50% for jewellery, 40% for investments and 10% in industry.