Spot Gold Price---> The purity of gold is measured in carats (youve probably heard about the diamond too), but most people do not really understand what a carat (no carrots!) Actually is. Pure gold has an index of 24 carats and is the type used in things like gold bullion bars. It is rarely used in jewelry (except in some Asian cultures), because it is too soft. In general, gold has added other metals, usually copper or silver, which makes it harder and more durable. If there is only one part of gold and 23 copper coins, gold would have a rating of 1 carat (1 ct), 2 parts gold and 22 copper coins 2CT gold, and so on. The credit rating of any element depends karat gold so what is the percentage of other metals are added to pure gold, the karat the more the better. In actual use, 22ct, 18ct, 14ct and 9ct are fairly common.