GOLD

Gold is a precious metal that has been valued by people since ancient times. People use gold for coins, jewelry, ornaments, and many industrial purposes. Until recently, gold reserves formed the basis of world monetary systems.

Gold is a very soft metal when it is pure (24 Kt. is pure gold). Gold is the most malleable (hammerable) and ductile (able to be made into wire) metal. Gold is usually alloyed (mixed with other metals, often silver and copper) to make it less expensive and harder. The scientific abbreviation of gold is Au.

The purity of gold jewelry is measured in karats. Some countries hallmark gold with a three-digit number that indicates the parts per thousand of gold. In this system, “750″ means 750/1000 gold (equal to 18K); “500″ means 500/1000 gold (equal to 12K).

Karat | Percent Gold
24 Kt. 100% Gold
18 Kt. 75% Gold
14 Kt. 58.3% Gold
10 Kt. 41.7%

Alloyed gold comes in many colors:

Colored Gold | Alloy Metal(s) Added to the Gold
Yellow Gold 50% silver and 50% copper
White Gold Nickel, zinc, copper, tin and manganese
Pink (rose) Gold 90% copper and 10% silver
Green Gold High proportion of silver or cadmium
Blue Gold Some iron
Grey Gold 15-20% iron