First look at the inspection agency. The state has strict qualification requirements for jewelry and jade quality appraisal institutions, and the appraisal certificate issued is only valid if it passes the review. The National Jewelry and Jade Certification Quality Supervision and Inspection Center is a national professional quality inspection institution authorized by the State Bureau of Quality and Technical Supervision according to law. It is the authoritative organization for the detection of jewelry and jade in China and has legal effect. The jewelry and jade appraisal certificate issued by it has the pattern of CMA (the symbol of measurement certification by the State Bureau of Quality and Technical Supervision), or cal and cncal, and one of these letters is valid, especially the first symbol CMA, which is the certification symbol required by the state. Consumers buy jewelry appraisal certificates with CMA logo, which largely proves the authority of the appraisal certificates used by merchants and the guarantee of product quality.

1, "CMA" consists of national or provincial metrological certification and accreditation institutions and accredited metrological certification units.

2. "CAL" is a nationally recognized testing institution.

3. "CNACL" has passed the testing organization approved by China Laboratory.

Second, look at the content of the exam. Including the name, color, purity, total mass, density, refractive index and other items of jewelry, these items are very strict in the nationally certified jewelry and jade testing institutions.

Third, look at the signature of the appraiser. The appraisal certificate must be signed by two appraisers before it is valid. One is an appraiser and the other is an auditor.

Fourth, look at the seal. Strictly speaking, it should be a steel seal, and the font on it can be clearly recognized.

Fifth, look at the quantity. There is the serial number of this certificate on the back of the appraisal certificate, which should be consistent with the serial number posted on the back of the physical object.

6. Some certificates can be inquired through websites or short messages.