What do you mean by 18K gold and 24K gold in gold?

18k gold refers to an alloy with a gold content of at least 75%. K gold is calculated by dividing pure gold into 24 parts, 18k gold is an alloy with a gold content of 18/24, and the remaining 25% is other precious metals, including platinum, nickel, silver and palladium. 18K gold is a kind of gold ornament with low cost and comfortable wearing.

24K is the color code of gold products. 24k gold is often considered as pure gold, but the actual gold content is about 99.99%. Some merchants even put forward the concept of "ten thousand gold" for speculation (the highest gold content can reach 999.9‰), but the statement of ten thousand gold has not been recognized by the state. In theory, 100% gold can be called 24K gold, but in reality it is impossible to have 100% gold, so China stipulates that gold with a content of more than 99.96% (including 99.96%) can be called 24K gold. Also known as thousands of gold.

Extended data:

According to the Regulation and Naming Method of Precious Metal Purity of Jewelry (national standard GB/T1KLOC-0/887—2002), the minimum purity of pure gold is 990, that is, the purity is not less than 990 ‰; The minimum purity of thousands of gold is 999, that is, the purity is not less than 999‰. In the standard here, the purity range of precious metals in precious metal jewelry does not include flux components, but the content of finished products shall not be lower than the specified purity range. The national standard on the purity of gold refers to the minimum purity. However, the purity of most pure gold and thousands of pure gold raw materials in the domestic market exceeds this minimum (the purity of pure gold reaches 995‰ and the purity of thousands of pure gold reaches 999.5‰).

References:

National standard of gold purity Baidu Encyclopedia