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.