How to identify natural A-grade jadeite for beginners

Look at the jadeite properties: When the jadeite grains are coarse, the jadeite properties can be clearly seen with the naked eye. When the grains are fine, the jadeite properties can only be seen with a magnifying glass. For high-end glass-bottom jadeite with extremely fine grains, the jadeite properties can only be observed with a microscope that magnifies it about 40 times.

Natural color: The color of natural jade spreads along the texture direction. The colored part transitions naturally with the colorless part. The color has a beginning and an end, and it looks like it grows from the inside of its fibrous tissue or granular crystals (commonly known as colored roots). It is calm and not empty. Green does not turn red when observed under a Charles filter, but appears gray-green.

Strong gloss: The polished surface has a glass or vitreous luster and a high refractive index. It is about 1.66. High-grade jade is like a pool of water, clear, transparent and beautiful.

High hardness: The hardness is 6.5--7, higher than all other jades.

High density: density is 3.34 per cubic centimeter. grams, suspended in diiodomethane.

No abnormalities on the surface: When observed under a gem microscope, the surface of most natural jade is an "orange peel structure". When the grains or fibers of jade are coarse, although the surface has some roughness or concave surfaces, it is relatively smooth, without reticulated structure or filling.

There are also a few natural jades that may produce obvious cracks and reticular structures due to the effects of material stress and weathering. When observed under a microscope, they are very similar to the cracks formed by acid corrosion, but such jades have no glue inside. With the help of a Raman spectrometer or an infrared spectrometer, accurate conclusions can be drawn.

Crisp sound: hit two jade pieces against each other, or use a jade block to hit the object being tested. If they are A-grade jade, they will make a crisp "steel sound", if they are not A-grade jade, the sound will be dull. However, listening to the sound is only for reference. To ordinary people, the sound of B-grade jade with "superb" counterfeiting technology and most of the C-grade jade is almost the same as that of natural jade.

There is no abnormality in the composition: the main chemical composition can be quickly and accurately determined by electron probe: sodium oxide - about 13%; aluminum oxide - about 24%.

If you are unable to identify the jade you purchased, you can go to the nearest jade identification agency for physical testing and ask the authority to produce the jade identification certificate.