How to identify "B-grade" jade products

B-grade jade is the product of natural jade raw stones that have been artificially processed at a later stage. Because its texture is not good enough and it contains many impurities, merchants beautify it in order to achieve sales purposes.

B-grade jadeite has a dull luster under natural light

The English word "bathe" means to wash, and the jade that has been bleached and filled is called 'B-grade' jade, also known as 'bleached jade'. Jade is washed by soaking it in strong acid to corrode and dissolve impurities and stains, making it clear and bright. Jade that has been washed with strong acid has a loose structure, and the cracks after acid etching must be filled. The vacuum negative pressure method is often used to inject transparent resin. The refractive index of this resin is close to that of jade, and after polishing it is almost indistinguishable from high-end jade.

The bleaching process of B-grade jadeite is mainly to remove impurities that affect the color and transparency of jadeite, fill and cover up the cracks in jadeite, reduce the brittleness of jadeite, and thus increase the beauty of jadeite.

Listen to the sound: If you tap it gently, you will find that the sound of B-grade jadeite is dull, while the sound of A-grade jadeite is crisp and pleasant.

The production process of B-grade jadeite:

1. Material selection: Jadeite varieties suitable for B-grade jadeite are mainly those with poor texture, dry type, poor base color, such as the Huaqing type and Tielong type, as well as other jadeite varieties with dirty base but green color.

2. Molding: The raw materials of jadeite are cut and shaped into semi-finished products according to the processing purpose. For example, if you want to make a bracelet, you should cut out the general outline first. Generally, the raw stone is not directly treated with acid and alkali or filled with glue. After being formed, the jade samples need to be cleaned in boiling water to remove oil stains left during the processing.

3. Acid soaking to remove dirt: Place the cleaned jade into a container filled with concentrated nitric acid and concentrated hydrochloric acid in a 1:1 ratio, and cook it at a low heat for half a month to remove the yellowing and dirt.

4. Soda ash loose structure: Wash the jade that has been soaked in acid with clean water many times, and then boil it in sodium hydroxide alkaline solution for about 1 month. During this period, the solution needs to be changed every 2-3 days. The purpose is to loosen the structure of the jade to make it easier to inject resin.

5. Injecting resin: Place the dried jade into a special sealed device equipped with a vacuum device, inject the prepared epoxy resin into the jade under a certain pressure, then take it out and place it in a constant temperature furnace to allow the excess filling to overflow.

6. Surface polishing: By polishing the jadeite with excess fillers removed, you can obtain B-grade jadeite with a better appearance.

Identification characteristics of B-grade jadeite:

Look at the color: The color of B-grade jadeite is too bright and yellowish, but the green color mostly has no color roots. It is quite the opposite. Due to the bleaching and filling treatment, the overall color is uniform and clean. Other colors disappear and the base appears pale when viewed against light.

Look at the luster: B-grade jadeite has a weaker luster, mostly resinous.

Look at the structure: B-grade jadeite is relatively loose, and when observed under magnification, it can be seen that the crystal grains are staggered, shifted, and have lost their directionality. When observed through light, B-grade jadeite has large grains and its transparency is consistent everywhere, which is not uniform.

The fluorescence of B-grade jadeite is relatively strong

UV fluorescence: Many resin glues fluoresce blue-white under long-wave ultraviolet light. If the blue-white fluorescence is particularly strong, it indicates that it is a "B-grade" product.

Look at the cracks: Also known as acid-etched reticulation, it is formed after jade is strongly corroded by acid, the gaps between particles are enlarged and filled with low-hardness resin glue, and then cut, ground and polished. The clarity of the cracks is related to the intensity of the acid wash, cutting and polishing of the jade.

Look at the base color: 'B-grade' jade is pickled with acid to remove impurities and make it very clean, but the light green and lotus root powder base will still exist. Observe the white part of the jadeite. B-grade jadeite will be particularly white, without any yellow or gray components.

Pits filled with glue: B-grade jadeite often has acid-etched pits filled with large amounts of glue, and you can even see air bubbles trapped in the glue.

Relative density: The relative density of B-grade jadeite washed with strong acid is smaller than that of natural jadeite, and it floats in the heavy liquid (diiodomethane) of 3.32.

Infrared spectrum: B-grade jadeite containing resin glue can detect the infrared absorption peak of the glue, among which the strongest and most obvious absorption peak is in the wavenumber range of 2800-3200cm-1. But sometimes there is another series of absorption peaks in the wave number range of 2200-2700cm-1, which is not obvious enough (only obvious when the amount of glue is large).

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