GOLD

GOLD

The one dollar US Sacajawea coin. Although it appears to be made of gold, it is not! It is an alloy of copper, zinc, manganese, and nickel.

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).

Source from http://www.enchantedlearning.com/jewel/pages/gold.shtml