Color. Judge the fineness of gold according to its color under strong light. Pure gold 999 is the highest value in jewelry color naming. The difference in gold content between Jinjin 999 and Jinjin 9999 is 0.9%, and the colors are slightly different.
The hardness of the texture. Quanjin 999 will definitely be harder than Quanjin 9999.
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:
Gold purity-Baidu encyclopedia