The content of silver (gold) in jewelry is not less than 99.0%. According to Zhihu's inquiry, the jewelry marked with 990 means all silver, and the content of 990 is 99% pure silver and 1% alloy. Because silver is soft, the jewelry is easy to deform. Now many handicraft manufacturers use 925 silver as jewelry, which also has a certain hardness and can be inlaid with precious stones to make high-grade jewelry. If 990 silver is used, it is widely used in industry.