Any brand you say is bullshit. The safest way to know the truth is to identify it yourself and make a proof as appropriate. Don't trust the certificates provided by others. Nowadays, fake certificates are rampant, and many certificates provided by jewelers are fake. Doing it yourself is king. You have to go to a national place to do it. A real certificate of 50 yuan ranges from tens of thousands of yuan. I have seen many jewelers who pay 50 yuan to issue certificates to their treasures, and even a pig brain can understand the credibility of this certificate.