A jewelry certificate is a third-party written record of a gemstone weight, dimensions, cut, color, clarity, and any treatment. A genuine report can be verified by its number on the lab website. GIA and IGI carry the strongest international recognition, NGTC is the leading national lab in China, and GIC is the gemology center of China University of Geosciences.

What Each Lab Covers

• GIA (Gemological Institute of America): The creator of the 4C diamond grading system. GIA reports are accepted worldwide, and high-value loose diamonds usually trade with a GIA report.
• IGI (International Gemological Institute): Headquartered in Antwerp, with strong recognition in diamond jewelry and lab-grown diamond markets and a wide lab network.
• NGTC (National Gemstone Testing Center): The authoritative national lab in China. Most silver-set jewelry sold domestically carries an NGTC certificate.
• GIC (China University of Geosciences Gem Testing Center): Known for semi-precious stones, jade, and jadeite assessment.

What to Check on the Report

First confirm the report number appears on the official website. For loose GIA diamonds, match the laser inscription on the girdle with the number on the report. The report must state whether the stone has been treated, such as filling, irradiation, or coating. Natural stones and treated stones differ widely in value. For fashion silver jewelry set with moissanite or cubic zirconia, factories usually provide an in-house inspection report or a commercial check report rather than an expensive GIA certificate, and this practice is standard in the industry. Grading can shift slightly between labs on color and clarity, so one report from the lab the buyer trusts is enough.

How to Spot a Fake Certificate

Fake reports share common traits: the number cannot be found online, the text is blurry or doubled, the weight and dimensions do not match the physical stone, or the lab name is misspelled. Genuine reports carry a QR code or a holographic security mark. For high-value diamonds or colored gems, ask the seller for a report that can be verified live online, and re-test the stone after delivery.

MASCOT Jewelry focuses on 925 silver fashion jewelry set with moissanite and cubic zirconia. Bulk orders can be arranged with customer-specified NGTC or SGS sampling inspections. The factory exports to more than fifty countries and welcomes brand clients to discuss inspection plans.