1. The certificate contains the photo, name, color, clarity, weight, density and refractive index of the inspected jewelry. Among them, it can be judged whether the photos, weight and appearance description are consistent with the real thing, so as to prevent the merchants from using the real certificate but changing the products.
2. There is usually a steel seal on the certificate. The steel seal of the formal certificate is deep and the imprint is clear. In addition, the appraisal shall be signed by the appraiser and the inspector.
3. official website, SMS and QR code scanning are also important methods. Of course, now all appraisal institutions, large and small, can set up their own inquiry systems, and what they can find is unreliable. The query can only determine whether the certificate really comes from the declared organization.
Extended data 1. There are five kinds of institutional qualification certification: CAL certification, CMA certification, CNAL certification, CNAS certification and ILAC-MRA certification.
2. Jewelry collectors must not rely solely on appraisal certificates. Certificates issued by authoritative organizations cannot fully explain the market value of jewelry. Even with a formal certificate, worthless jewelry is still worthless. Especially jade ornaments, have always attached great importance to the origin "life experience". For example, Hetian jade, Qinghai material, Russian material and Korean material can generally be called "Hetian jade", but the price gap is very large, and the appraisal certificate can't prove its origin.