Precious Metals - Karat Unit of Fineness
Units of fineness - Karat.
The fineness of gold in coins, bars or jewelry is commonly measured in "karat" - parts per 24 - where
- 24 karat = 24/24 = 1 = 100 % = 1000.00 o/oo
- 18 karat = 18/24 = 0.75 = 75 % = 750.00 o/oo
- 14 karat = 14/24 = 0.583 = 58.3 % = 583.33 o/oo
- 8 karat = 8/24 = 0.333 = 33.3 % = 333.33 o/oo
Pure gold is yellow in color. Gold is commonly alloyed with silver, copper, nickel and zinc. White gold is an alloy with nickel, copper and zinc. Note that
- 24 karat gold - 100% - very soft, not recommended for jewelry
- 22 karat gold - 91.7% - soft, not recommended for jewelry
- 18 karat gold - 75% - recommended for fine jewelry
- 14 karat gold - 58.3% - used in average jewelry
- 12 karat gold - 50% - not acceptable in jewelry
- 10 karat gold - 41.7% - the lowest limit for products in "real" gold