The identification basis of Hetian jade in national standards is as follows:
nephrite
5.2.2. 1 English name: nephrite.
5.2.2.2 Mineral (Rock) Name: Tremolite is the main mineral.
5.2.2.3 material properties:
Chemical composition: Ca2(Mg, Fe)5Si8O22(OH)2.
Crystalline state: crystalline aggregate, usually fibrous aggregate.
Common colors: light green to dark green, yellow to brown, white, gray and black.
White can be called white jade, dark green and grayish green can be called sapphire, and between white jade and sapphire is sapphire.
Gloss: glass luster to oily luster.
Cleavage: Tremolite has two sets of perfect cleavage, and usually no aggregate can be seen.
Mohs hardness: 6 ~ 6.5.
Density: 2.95(+0. 15, -0.05) g/cm3.
Optical characteristics: heterogeneous aggregate.
Polychromaticity: None.
Refractive index:1.606 ~1.632 (+0.009, -0.006), and measuring method: 1.6 1.
Birefringence: not measurable.
Ultraviolet fluorescence: None.
Absorption spectrum: absorption lines are rarely seen, and fuzzy absorption lines can be seen at 500nm. High-quality green nephrite will have a fuzzy absorption line in the red area.
Magnification inspection: fiber interwoven structure, black solid inclusions.
Special optical effect: I have never seen it.
5.2.2.4 optimization processing:
Wax dipping: filling surface cracks with colorless wax or paraffin wax. Hot needle is easy to melt, and the absorption peak of organic matter can be seen in infrared spectrum.
Dyeing treatment: whole or partial dyeing. Often dyed green, the dye is distributed along the grain gap, and the absorption spectrum shows an absorption band of 650nm.
Extended data:
Identification laboratory: NGTC
The National Jewelry and Jade Quality Supervision and Inspection Center (hereinafter referred to as the Inspection Center) is a national professional quality inspection institution authorized by the relevant competent departments of the state according to law, and it is the authoritative institution for 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 revises relevant national standards. It plays a guiding role in standardizing the domestic jewelry market and promoting the healthy development of the jewelry industry.
It is a national professional quality inspection institution for jewelry and jade authorized by AQSIQ according to law. It has passed the national metrological certification, the laboratory ISO/IEC 17025 accreditation of China National Accreditation Committee for Laboratories, and the national product quality supervision and inspection institutions. It is the authoritative organization for jewelry and jade testing in China.
The center has first-class laboratories in Beijing and Shenzhen. The center has gathered a large number of outstanding professional and technical personnel, has advanced testing equipment in the world today, and has established a scientific and rigorous quality management system in accordance with international standards. Personnel, technology and management have reached the international advanced level.