The reason for this is the following：
1, unintentional loss
First, the jewelry products are combined with 50 pendants of the same color and size, and 50 certificates, so you can accidentally change the packaging. Factory distribution, gold store warehousing, showcase placement, goods transfer, etc. may all go wrong.
B, the factory used a stone to order goods A and issue the certificate, but the mistake was that goods A used stone B and issued the certificate, there would be some, because sometimes 500 pieces were the same goods, and the inspector was not careful. One or two B stones out of 498 A stones can also be regarded as A stones. This problem will occur in the process of manual inspection, and people are not machines. I have several SI diamonds that have been certified as VS, ha. . .
C, other reasons (can't say here. . . )
2. Intentional fraud
A. Unscrupulous merchants will return others' old diamond certificates, then match them with diamonds with corresponding data, and mark them as new diamonds for sale. To break this trick, please see my answer. One issue talked about this. ) Black businesses are even worse! Make it with a fake drill.
B, made 100 pieces of the same diamond ornaments, of which only one piece was VS grade and the other 99 pieces were SI grade, so he made a VS certificate and then copied 99 pieces. What to buy? Online search says it's true. The goods are on the plate.
C, other reasons (can't say here. . . )
The above is my opinion, I hope I can help you. If it helps, please choose my best answer, and I will continue to answer your follow-up questions.