I bought a 1 carat diamond ring in Chiba, but I didn't have a 4c gia certificate. I only have a jewelry and jade appraisal certificate, but there is no diamond grade on this certificate. Can there be any guarantee? Why is there a 4c standard GIA certificate? Please give me the certificate number and the weight of the diamond. I'll check. I haven't heard of it at all. Also, if it is mosaic grading, it is the most correct to take it down. And if it is tested in China, basically GIA will be downgraded. This is very common, because the rating emphasis of the two testing institutions is different.