How to identify A, B, and C grade jadeite?

1. Jade A, B and C grades

1. A-grade jadeite

Grade A jade refers to pure natural jade that has not been artificially processed by physical or chemical means to change its internal structure.

Its characteristics are that the specific gravity should be between 3.25-3.43, the refractive index should be 1.66, and the surface should have a strong glass luster. Observed under side light with a 40x magnifying glass, the surface is smooth and bright, the gaps between mineral particles are fine and clear, and the sand holes, which are related to the strength and direction of polishing, are generally triangular or polygonal strips, with straight edges and no signs of dissolution. These sand holes are usually distributed individually and rarely connected. Under normal circumstances, they only appear locally.

2. Class B Jadeite

B-grade jadeite refers to those jadeites that originally have poor water quality and color. They are artificially soaked and bleached in strong acid to release some impurities inside the jadeite, and then injected with high-molecular polymers using some high-tech means to improve their water quality and color.

3. C grade jadeite

C-grade jadeite refers to jadeite that was originally colorless or light-colored, but has been treated with chemicals or radiation to add or change its original color.

2. Identification of A, B and C jadeite

Many books and articles have discussed how to distinguish between A-grade, B-grade and C-grade goods, but some recommended identification methods lack operability, such as infrared spectroscopy and laser Raman spectroscopy. As an ordinary collector, these instruments and equipment are not only unaffordable, but also difficult to obtain even if you can afford them. The identification based on the feeling of some experts is even more difficult for beginners to master.

For example, the green color of B-grade jade has a feeling of being dissolved and floating; after being injected with glue, the green color of B-grade jade is weakened and it appears hazy. This feeling is the experience gained by a professional after years of identification of A and B goods. It is not easy for ordinary collectors to master it in a short period of time.

A-grade jade is lighter in color and slightly rough in texture. After acid washing and color enhancement, it has bright color and a fine base.

So, for a collector who is new to this field and has only a few simple tools (a 40x magnifying glass, a strong flashlight, a balance or diiodomethane, a refractometer or monobromonaphthalene), how should he distinguish between A-grade, B-grade and C-grade products?

The author believes that we should start with density first. That is to say, every time you get a piece of jade, the first thing you need to do is to measure its density. Any value lower than 3.33 should attract attention. The reason is simple. Although the density of jade is defined between 3.25 and 3.43, the texture of jade with a lower density will not be very good even if it is A-grade jade. And the possibility of jade with a density above 3.33 to become B-grade jade is lower. Because not all jade is suitable for being B-grade jade.

Generally speaking, B-grade jade has a rough and loose texture, poor transparency, and contains yellow-brown and black speckled substances. In addition, from the color point of view, jadeite suitable for being B-grade must be green. But not all jadeite with green color is worth working with. Only those jadeite with better green color but low transparency and many impurities in it are worth working with. What’s more important is that most of the materials used to process B-grade jade are now made from 83 jade. However, the relative density of 83 jade is lower than 3.33, ranging from 3.25 to 3.31. This provides us with a reference data to correctly identify A goods and B goods.

Secondly, you need to carefully observe the surface characteristics of the jadeite, and observe it with the side light of a 40x magnifying glass (oblique lighting method). The surface of A-grade jadeite is as smooth as a mirror, with clear grain boundaries and an uneven topographic effect. There are some small sand holes, and the pits appear in the shape of triangles or polygonal strips where the sand grains meet. The sand holes and pits of B-grade jade are mostly in the form of dissolution holes, which are round, deep, black, and have blunt edges.

In addition, the surface of B-goods is covered with uneven lines, criss-crossing webs, and tree-branch grooves, just like an aged asphalt road. Although fine lines can be seen on the surface of A-grade jade, they are the grooves between the particles. Some A-grade jades with inferior texture will often have some grooves due to poor polishing, but these grooves only appear in the parts that are difficult to polish, and there are no signs of deep etching on the edges.

The identification of A and B grade jade bracelets is generally based on listening. If there are no cracks, hang up a bracelet with your fingers, pick up another bracelet or other hard object and tap gently (be sure to tap gently, using too much force will damage the bracelet and the sound may be wrong). The sound of A grade bracelet is crisp, long and echoing, and has a metallic sound; the sound of B grade bracelet is dull and hoarse.

It is relatively simple to identify C-grade jadeite, usually by shining a strong flashlight through it. The green color of A-grade jade has a colored head and tail, with a transition from light to dark that forms spots and stripes. However, under strong light, the green color of C goods is evenly distributed around the grains or in the cracks in the form of fine lines.

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