Scientific selection and identification of jadeite

Jadeite is known as the Oriental treasure. It is an internationally recognized type of jade and is recognized as the king of jade. Generally, we define fibrous aggregates and stone polycrystalline aggregates composed of pyroxene minerals mainly composed of jadeite minerals as jadeite. Its main crystal phases are sodium chrome pyroxene and omphacite. Due to its high economic, collection, health and ornamental value, jade has always been the most expensive one in the jewelry market. In recent years, as the jade market has gradually become more popular, the price of jade has continued to rise. Such high prices have attracted many unscrupulous businessmen in the market who take the opportunity to make huge profits. So how should consumers identify and choose to avoid paying the "IQ tax"?

Grade A (Type A): Real jade, that is, naturally formed, without any artificial processing. It is also the only type with collection value and appreciation potential.

B-grade jade (category B): natural jade with inferior texture or semi-finished raw materials that have undergone artificial physical and chemical treatment to improve their texture, color and transparency. Low collection value.

C goods (Type C): Jade or raw materials that are inferior to Type B. They are artificially treated physically and chemically and then dyed (mainly green and red). This type of jade has absolutely no value in terms of preservation and collection, and is generally not suitable for wearing.

D goods (Type D): It is not jade at all, but an imitation of other inferior stones that have been treated with strong acids, dyes, etc. Not only does it have no collection value, but wearing it can cause harm to the human body.

Learning to distinguish the types of jade is the basis for selecting high-quality jade.

Identification methods

1. Experience Identification

Class A and Class B jadeite have ideal transparency, natural color and softer luster. According to the transparency, it can be divided into fully transparent, transparent, translucent, slightly transparent and opaque. Since categories B, C, and D need to be treated with chemicals, they will cause irreversible damage to the glass luster of jade, making it appear waxy.

Under strong light source,

• When light penetrates more than 10 mm into the jadeite, it is an old glass variety and is basically colorless jadeite;

• The light penetration into jade is 6~10 mm, which belongs to the old glass variety, and is basically colorless jade or light-colored jade;

• The light penetration into jade is 3~6 mm, the jade is of good quality and generally belongs to Class A;

• When light penetrates into jadeite at 1-3 mm, the jadeite has a relatively good texture and is generally classified as Class B.

• If light cannot penetrate the jade, it is generally type C or D.

• Type B jadeite fluorescence identification method: Take a UV light source and irradiate a certain part of the jadeite at an angle of 30~75°. If the light color is pure and bright, no fluorescence is produced, there is no color change, and the light transmittance is good, it is not Class B. If green fluorescence appears, it indicates the presence of glue-like substances, which belongs to Class B.

2. Specific gravity identification

Scientific data shows that the specific gravity of most jade remains between 3.25 and 3.40 (compared with pure water). Prepare 3.32 heavy liquid as the standard test liquid, and observe whether the target sinks and the sinking speed to judge. Generally, Class D sinks the fastest, Class C sinks slowly, and the difference between Class A and Class B is small, so the measured values ​​can be used for comparison to make a judgment.

3. Other identification methods with the help of equipment: With the help of professional equipment, more accurate results can be obtained than intuitive feelings. Generally, identification agencies use instrument-assisted identification. Mainly includes

• Refractive index identification method: identification is carried out with the help of a refractometer;

• Structural identification method: with the help of professional equipment such as microscope;

• Spectroscopic identification method: Infrared spectroscopy mainly uses infrared spectrometer for identification, and spectroscopic identification uses spectroscope for identification

• Color filter identification method: using color filters as a tool

Since the above identification method requires the use of professional equipment and is too professional for jade enthusiasts, it will not be described in detail.

It should be noted that as a natural gemstone, natural defects are generally unavoidable. It cannot be said that gemstones that are too perfect do not exist, but the chances of fraud are greater. We cannot simply think that a certain color of jade is more valuable. Every type of jade has its advantages and disadvantages, and needs to be considered comprehensively. Finally, the rule of thumb is to look more and buy less to avoid being taxed by intelligence!

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