I work in a jewelry store. As long as it is a big store, I can basically buy it with confidence. As for purity, it depends on what kind of gold you want to buy. National standards include pure gold and thousands of pure gold. As long as the content of pure gold reaches 99.0%, it can become pure gold, and the content of thousands of gold reaches 99.9%. Thousands of gold can also be called pure gold. Strictly speaking, as long as there are artificial solder joints, the NDT room will not reach 99.9%, because the solder joints are pure gold or gold with a gold content of only 90.0%, and their melting point is lower than thousands of pure gold according to the process requirements, so all these are needed, except gold bars or inverted mold rings, the circle with flowers should have some solder joints, (99 may only be 99. 1-8%). This article is not plagiarized, please adopt it.