The carat system (Karat in the USA) is used to indicate the metal composition of jewellery in most countries around the world. The higher the carat the purer the gold or metal is.

How the gold is used determines the amount of gold in relation to other metals. Pure gold is actually very soft, and in order to be useful for example, in manufacturing jewellery, it is alloyed with several other metals to increase its hardness and durability.

Gold readily creates alloys with metals such as silver, copper, zinc or nickel. The ratio of gold and alloys can be modified to obtain certain colours (e.g. rose gold or white gold). Today manufacturing jewellers prefer nickel-free alloys as many people are allergic to the nickel in jewellery.

Gold comes in several carats, the purest being 24 carat gold which is also the most expensive. It also comes in 22 carat, 18 carat, and 9 carat gold, 18 carat being used widely in the manufacturing jewellery industry for its rich colour and durability. Most gold jewellery will be stamped with its carat (K or Kt), for example, on the inside of gold rings and bracelets.

The price of gold jewellery is based on it’s purity (carat), design and construction and current market price. Alloys add weight to gold, and so weight cannot be used to accurately determine the price.

Gold Purity: Quick Reference GuideDetermining Your Gold Carats

24 carat – 100% gold

22 carat – 91.7% gold

18 carat – 75.0% gold

14 carat – 58.3% gold

12 carat – 50.0% gold

10 carat – 41.7% gold

9 carat – 37.5% gold

Check out PMT’s range of Gold and Precious Metal Supplies for manufacturing jewellers.