Second, we should pay attention to the units and personnel with certificates. The identification and classification of diamonds is a highly technical job, which must be carried out by professionals who have received professional training and obtained relevant authoritative qualification certificates, using various advanced testing equipment and in a good environment. All three are indispensable.
Three, at present, China's units with these conditions are roughly:
(1) Relevant institutions of higher learning: such as Peking University, Tongji University, East China University of Science and Technology, Nanjing University, China Geo University, Chongqing University, etc.
(2) National quality and technical supervision departments and a few scientific research units engaged in gem research, such as Beijing National Jewelry Quality Testing Center and Shanghai Technical Supervision Bureau Jewelry Quality Testing Center.
(3) Relevant units of the Geology and Mineral Resources Department.
(4) Relevant scientific research institutes. Therefore, when looking at the diamond appraisal classification certificate, we should first check whether the certificate is the above authority; The second is to check whether the appraiser has the above-mentioned authoritative qualification certificate.
Fourth, pay attention to the content of the appraisal certificate. Due to different testing units, the format of the certificate may be different, but the basic contents contained therein are roughly the same.
5. The standard appraisal grading certificate shall include the following contents: the name of the certificate, the physical parameters such as the shape, size, weight, clarity, color and cut of the diamond, a brief comment, attached photos, the signature of the appraiser (qualification, DGA, GIA, FGA or HRD), the signature and qualification of the auditor, the name and address of the appraiser, the special seal for the appraiser, the date of signature, etc.
Six, the anti-counterfeiting inks used in the jewelry anti-counterfeiting appraisal certificate are: fluorescent ink, watermark ink, color-changing ink, glare ink, photosensitive ink and OVI ink. Anti-counterfeiting certificates generally use four-color plus spot color printing or gravure printing.
Seven, the main anti-counterfeiting means used in the certificate are: group flower, lace, relief, microfilm, invisible watermark anti-counterfeiting, ultra-precision printing, color fiber anti-counterfeiting, anti-copying group flower, anti-scanning, etc.