Pure gold is a kind of gold. Pure gold is used to indicate the gold content of gold. Gold with a gold content not less than 99% is called pure gold. Pure gold can also be expressed as "990 Gold", "gold990" or "g990".

The purity of gold jewelry is also the gold content. Pure gold is 24K, and the gold content of 1K is about 4. 16%, so the percentage of gold content can be converted into the representation of k gold. The common one is 18K gold, which has high hardness and is mostly used for inlaying jewelry.