Does jadeite raw stone also need to be identified? Which is better, primary ore or secondary ore?

Jade is a high-pressure, low-temperature metamorphic rock. After it is formed into jade, the ore body is broken and destroyed due to tectonic geological actions and strong crustal movements, forming gravels of varying sizes.

Some of these gravels remain in place, while others are transported to the downstream of the river and deposited. Some gravels accumulated on the residual slopes or in the downstream river channels form secondary deposits of jadeite. Currently, the raw materials on the jade public auction include both primary ores mined from primary deposits and secondary ores.

▲Native jade (primary ore)

A statistical analysis of the raw materials from the Myanmar public auction shows that the number of secondary jadeite mines is far greater than that of primary mines, and the quality grade is generally higher than that of primary mines. High-quality jade raw materials almost without exception appear in secondary mines, and are produced in the form of round, semi-round and angular gravels of various shapes and sizes.

Due to the effects of surface weathering, water and rocks, secondary jadeite minerals often form a surface layer of varying thickness, covering the "flesh" (jadeite) and concealing the jadeite's color, type, bottom, cracks, and streaks, so secondary minerals are also called gravel jade and water stone jade . In the market, they are divided into covered materials, window materials, sheet materials , etc. according to their performance characteristics. Since the primary jade ore body is not covered by a surface cortex, the material characteristics of the jade can be directly observed, and it is also called primary jade.

▲Gravel jade (secondary ore)

As for the identification of jade raw materials, since jade raw materials are large and not suitable for laboratory analysis and testing, the main method used is observation with the naked eye , which is simpler and more effective.

1. Water immersion observation

Common fake wool materials are made into fake leather and fake "windows", in which you can see the glue and joint surfaces (seams) used for bonding. These artificially added glues and joints (seams) have a different refractive index from jade and can be easily observed in water. In addition, fake leather made with other sand mixed with cement also performs differently in water than real jade leather.

2. Tapping or weighing

A simple hammer test can also help identify genuine and fake jade raw materials. Fake materials with joints have cracks in the middle, which hinder the propagation of sound waves. The echo when knocked is also slightly different from that of natural materials.

The purpose of weighing is to try to find out the density (specific gravity) of jade . The density of jadeite raw materials is around 3.33, and jade that deviates from this density value is questionable. Experienced experts will also weigh the jade with their hands and sometimes be able to tell whether it is real or fake.

3. Knife scratching experiment

The wool material with skin has a low hardness due to weathering (not reaching Mohs hardness 6.5~7.0), but it cannot be scratched by a steel knife, only a small amount of sand on the surface will fall off. The raw material for fake leather made of cement mixed with sand can be scratched by a knife, and the surface gravel can easily fall off in pieces.

4. Simple instrument observation

You can use a magnifying glass to observe the structure of jade and the characteristics of jadeite minerals . Jadeite structure and particles can sometimes be observed on the surface of natural jade raw materials; the mineral particles of fake rough materials are disorganized or no jadeite particles can be seen.

You can also use an ultraviolet fluorescence meter and Charles filter to observe the luminescence phenomenon of jade raw materials.

Natural green jadeite has no fluorescence under an ultraviolet fluorescence instrument, but jadeite that is artificially dyed or has glue on the surface can sometimes be observed to fluoresce. Under the Charles filter, dyed and viscose jade raw materials can sometimes be seen as dark red, but it should be noted that some jade raw materials containing hydrogrossular garnet will also appear dark red.

In addition to observation with the naked eye, jade raw materials can be tested in the laboratory with the help of large instruments, namely infrared spectrometers and Raman spectrometers . The mineral composition of jade can be analyzed to determine the authenticity of the jade raw materials.

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