National Inspection (NGSTC) Diamond Certificate: National Gold and Silver Products Quality Supervision and Inspection Center (Nanjing) (hereinafter referred to as the Center) is a national product quality supervision and inspection institution established by the General Administration of Quality Supervision, Inspection and Quarantine according to law, and has passed the national metrological certification, national examination and approval, and national laboratory accreditation. Undertake quality supervision and spot check, arbitration inspection and entrusted inspection of precious metals, jewelry and jade products nationwide.

International GIA Diamond Certificate: GIA Gemological Institute of the United States is the founder of promoting the internationalization of diamond appraisal certificate. It was established in Los Angeles on 193 1 and is an independent non-profit organization. As the authority of the world gem industry, GIA is famous for its fairness. Because GIA does not involve for-profit business, it will not be affected by human factors on the premise of reputation first, so it has great credibility in the content quality of the appraisal book.

Because they are independent and authoritative testing institutions in two different regions, there must be subtle differences in testing standards, such as:

1, GIA only issued the classification certificate for loose diamonds.

2. The national inspection has grading certificates for loose diamonds and diamond-encrusted diamonds. Generally, we refer to the classification certificate of diamond-encrusted diamonds in the national inspection.

3.GIA's testing standards tend to cut diamonds.

4. The national inspection standards tend to be the color and clarity of diamonds.

5. The data of 5.GIA certificate is more detailed.

6. The data of 6.NGTC certificate is somewhat simplified.

7. There is basically no difference in the identification above 1 carat, but there may be differences below1carat.