Is there a master who knows jewelry? Is it true?/You don't say.
As a testing professional, I can only tell you that such a certificate has no practical significance, unless you find it is false after testing or seriously inconsistent with the seller's promise, you can get 100% compensation for returning the goods, and then take it to a competent and qualified institution for appraisal, but the cost is high and it is charged according to the testing items. If you can't return it and there is no need to test it, buy a toy.