GOLD Gold is a precious metal that is very soft when pure (24 Kt.). Gold is the most malleable (hammerable) and ductile (able to be made into wire) metal. Gold is alloyed (mixed with other metals, usually silver and copper) to make it less expensive and harder. 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). 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
WHITE GOLD White gold is gold that has been alloyed with a mix of nickel, zinc, copper, tin, and manganese (and sometimes pallladium). White gold was originally developed to imitate platinum during World War II (during this time in the US, platinum was considered a strategic material and its use was prohibited for most non-military applications, like jewelry making). White gold jewelry is sometimes plated with rhodium.
YELLOW GOLD
Yellow gold is gold that has been alloyed with a mix of 50% copper and 50% silver.
Karat
Percent Gold
24 Kt.
100% Gold
18 Kt.
75% Gold
14 Kt.
58.3% Gold
10 Kt.
41.7%
KARAT
Karat (abbreviated Kt) is a measure of the fineness of gold. 24 karat gold is pure gold. 18 karat gold is 18/24 gold (about 75% gold - three quarters gold). 14 karat gold is 14/24 gold (about 58% gold - a little over half gold). 12 karat gold is exactly half gold. 10 karat gold is 10/24 gold (only about 43.5% gold - less than half gold).
