1. Look at the certification marks such as CMA, CAL or CNAS of the testing organization. CMA must appear.
2. The certificate contains the photo, name, color, purity, weight, density and refractive index of the inspected jewelry. Among them, you can judge whether the photos, weight and appearance description are consistent with the real thing, so as to prevent merchants from using genuine certificates but changing products. Certificates generally have steel seals, and formal certificates have deep steel seals and clear marks. In addition, the appraisal shall be signed by the appraiser and the inspector.
It is worth noting that in order to prevent some merchants from selling dog meat with genuine jewelry, it is necessary to carefully check whether the photos on the certificate look the same as the jewelry purchased, and then weigh the total weight (there may be some errors in the electronic scale). If it's all the same, don't worry, the certificate is real and the jewelry is real.
4. 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.
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.
Certificate GIA
The certificate of diamond appraisal issued by Gemological Institute of the United States proves that internationally renowned diamond appraisal institutions have laser codes consistent with the certificate on the waist edge of diamonds, which can also be inquired in official website. GIA was founded in Los Angeles 193 1. It founded and put forward the international scoring system.
Headquartered in Los Angeles. The college is trusted by the world in diamond classification and gemstone identification, and is famous for its knowledge and expert position in gemstones. In fact, GIA diamond classification report and GIA diamond processing are considered to be the first gem certificates in the world. Diamonds of all sizes are sent from all corners of the world to the college for analysis and classification.
The breakthrough research of American Gemological Institute and its own education, experiment and equipment development process are almost the chronicle of the growth of jewelry industry. Since 1953, Richard T. Liddicoat founded and popularized this international diamond grading system, it has become the most respected and authoritative diamond grading appraisal institution in the United States.