General method of identification of jewellery and jade

2021-08-21

In the identification of jade, generally speaking, the identification methods are divided into two categories: conventional identification methods and special identification methods.
In the "Jewelry and Jade Appraisal", the conventional appraisal method is an item that needs comprehensive testing in the normal testing process. Comprehensively judge the test results of each item to ensure the accuracy and uniqueness of the test conclusions. Routine identification includes: naked eye observation, magnification inspection, refractive index, birefringence analysis, optical characteristics, color identification, density and other parts. The identification methods commonly used in jade appreciation and jade trade can generally be classified as conventional identification methods.
Generally speaking, the identification of jade should be based on the hardness, transparency, color, brilliance and other aspects. Compared with counterfeit products, real jade is very hard and wear-resistant, crystal clear and pure in color. Folds on the surface, bubbles inside, light weight, and low hardness are all common features of fake jade.
The following specifically introduces the commonly used jade identification methods:
1. Appreciation of gloss: No matter translucent or opaque, real jade has a warm luster, grease luster, natural pattern, and the internal fiber state is not easy to imitate. It is normal if there is a small amount of impurities or cotton-like patterns inside; the fake jade is dry in color, dull and dull, and there are air bubbles;
2. Hardness measurement: Use a knife to engrave and scrape, the real jade does not leave a trace. Taking the glass plate (Moore hardness 5.5) as the standard, with the exception of Xiuyu and turquoise, streaks can generally be made on the glass plate, and the jade itself is not damaged at all. Fake jade is generally soft and cannot scratch the glass.
Common fake jade is generally made of plastic and glass. They are all amorphous materials, with low hardness, low density, and essential characteristics of the material. For example, the plastic can be moved with a steel needle, or scratches can be carved, and it can be held lightly in the hand. The glass shows bubbles inside under the light or sunlight, shows amorphous under the polarized lens (no periodic light and shade changes when rotating), and has raw materials to make swirling stripes, etc.
3. Gravity: The real jade has a heavy hand feel, while the fake one is light. This is actually related to the density of jade, real jade has a fine structure, while fake jade is mostly imitated by plastic and glass. Compared with the volume, the weight of real jade far exceeds the weight of its counterfeit products;
4. Listening to the sound: Hang the jade in the air with a string and knock it with a hard object. The authentic sound is crisp and pleasant, with a melodious aftertaste; the fake one is relatively dull and dry.
5. Look at the fracture: Observed with a 10x magnifying glass, the fractures of real jadeware are uneven, showing a relatively fine structure; the fractures of fake jadeware are neat and shiny, often glass-like imitations, with rough fracture structure and no waxy luster It is a stone imitation.

In general, using conventional jade identification methods to identify the authenticity and quality of jade, you can get accurate conclusions. In some special cases, special identification methods will be used for problems that cannot be solved by the application of conventional identification methods. The special identification method is not applicable to all jade identification, but a targeted identification method. For example, some jade has a special thermal conductivity, you can distinguish the authenticity of the jade based on the heat conduction performance of the jade; and some jade with special chemical properties meets certain chemical substances due to its structure, composition, and composition. Or foreign substances will undergo chemical reactions. According to the phenomenon and degree of the reaction, we can also identify the authenticity of the jade; it is worth noting that some special identification methods may cause varying degrees of damage to the identified samples, so we must Be cautious. Now, there is also a special identification method that applies the principle of spectral analysis to identify gems and jade, which is called non-destructive identification. It is also a very good means of technical identification.