I don't know about other places. We are local experts in China Gemstone Association. Gao Guozhi, Gao Deliang and tian teacher are all authorities with deep qualifications. In fact, ordinary appraisal does not need to pursue particularly famous or authoritative experts, as long as it is a professional jewelry appraiser. Related books If you study geology, buy General Geology, which is more authoritative. If you want to study jewelry, you must study systematic gemmology, which is the most authoritative. I'm a jewelry major and I've learned a lot. Systematic gemmology can be said to be an all-encompassing encyclopedia of the jewelry industry.