The certificate has a number on it. You can know whether the certificate is genuine by checking it with a professional jade appraisal agency. If the certificate is genuine, you can rest assured, even if the item is fake and issued by a quality inspection agency. If you get the wrong certificate, you will be compensated.

The identification basis of Hetian jade on the national standard is as follows:

5.2.2 Nephrite jade

5.2.2.1 English name: nephrite.

5.2.2.2 Mineral (rock) name: The main mineral is tremolite.

5.2.2.3 Material properties:

Chemical composition: Ca2(Mg,Fe)5Si8O22(OH)2.

Crystalline state: Crystalline aggregates, often in the form of fibrous aggregates.

Common colors: light to dark green, yellow to brown, white, gray, black.

White jade can be called white jade, dark green and gray-green can be called sapphire, and those between white jade and sapphire are sapphire.

Gloss: glass gloss to grease gloss.

Clearness: Tremolite has two sets of complete cleavages, and aggregates are usually missing.

Mohs hardness: 6~6.5.

Density: 2.95 (+0.15,-0.05) g/cm3.

Optical characteristics: heterogeneous aggregate.

Multiple colors: none.

Refractive index: 1.606~1.632 (+0.009,-0.006), point measurement method: 1.60~1.61.

Birefringence: Not measurable.

UV fluorescence: None.

Absorption spectrum: Very rare absorption lines, fuzzy absorption lines can be seen at 500nm, and high-quality green nephrite can have fuzzy absorption lines in the red area.

Magnified inspection: fiber interwoven structure, black solid inclusions.

Special optical effects: not seen.

5.2.2.4 Optimization treatment:

Wax dipping: Fill surface cracks with colorless wax or paraffin wax. The hot needle can be melted, and the absorption peak of organic matter can be seen in the infrared spectrum.

Dyeing treatment: Dye the whole or selected parts. Often dyed green, the dye is distributed along the particle gaps, and the 650nm absorption band is visible in the absorption spectrum.

Extended information:

Appraisal laboratory: NGTC

The National Jewelry and Jade Quality Supervision and Inspection Center (referred to as the Inspection Center) is authorized by the relevant national competent authorities in accordance with the law. A national-level professional quality inspection agency for jewelry and jade, it is the authority on jewelry and jade testing in China. The inspection center provides entrusted inspection services to the society, undertakes national market supervision and inspection, arbitration inspection, import and export commodity inspection, and formulates and revise relevant national standards and other tasks. It plays a guiding role in regulating the domestic jewelry market and promoting the healthy development of the jewelry industry.

It is a national-level professional jewelry and jade quality inspection agency authorized by the General Administration of Quality Supervision, Inspection and Quarantine in accordance with the law. It has successively passed national metrology certification, laboratory ISO/IEC 17025 accreditation by the China National Laboratory Accreditation Board, and review and approval by the National Product Quality Supervision and Inspection Agency. It is an authoritative organization in domestic jewelry and jade testing.

The center has first-class laboratories in Beijing and Shenzhen. The center has gathered a large number of outstanding professional and technical personnel, has the most advanced testing equipment in the world, and has established a scientific and rigorous quality management system in accordance with international standards. Personnel, technology and management have all reached the international advanced level.