The concept of A-grade jadeite Many friends who have never come into contact with jade are unfamiliar with the term A-grade jade. They do not understand what A-grade jade means, and even use the name of A-grade jade in other industries to look at A-grade jade (A-grade in shoes stands for high-quality prevention of inferior products). In fact, in the jade industry, A-grade jade is synonymous with natural and pure. "A-grade jadeite" does not refer to the most valuable jadeite, nor the most beautiful jadeite, but to natural jadeite. People all like jadeite with bright colors and good quality, but such high-quality natural jadeite is rare after all and is very expensive; there are not many with good colors and slightly worse quality, most of them are of poor color, coarse quality, and without water. The contradiction between this market demand and the small output of high-quality jade is becoming increasingly acute. Many merchants try to improve or change the color and transparency of poor-quality jade through artificial optimization processing, resulting in what is now commonly known in the industry as B goods, C goods, and B+C goods. Grade A jadeite refers to jadeite that has only undergone mechanical processing without any artificial chemical treatment, and its color, structure, transparency, etc. remain in its natural state, that is, natural jadeite. A-grade jade does not refer to the grade of jade, but emphasizes that the jade is natural. As various counterfeiting technologies continue to improve, fake and inferior jade is flooding the market. As a jade collector, if you cannot distinguish them yourself, you can go to a nationally recognized jewelry appraisal center and ask professionals to appraise them. Note: The grains of A-grade jade have clear outline boundaries, there is sufficient water between the grains, the surface is very smooth, the color is irregularly distributed in clumps, and the boundaries between the color blocks are clear. B-grade jadeite: It is low-grade jadeite that is acid-washed and injected with glue to impersonate high-grade jadeite. The mineral composition of B-grade jade is the same as that of natural jade, and the color is natural, but the filling glue will affect the brightness of the color, as well as the transparency and gloss after aging. B-grade jadeite has a very good water content, which means it has a glossy luster and a dull sound when knocked, and is relatively cheap. But good B-grade goods are more valuable than bad A-grade goods (don’t think that A-grade goods are necessarily valuable, there are also A-grade goods that are made of bricks and are worthless). B-grade products made using the latest technology are very close to A-grade products. Note: B-grade jade is mostly translucent to slightly transparent, and looks dull and dull. It does not have the brightness and watery feeling of natural jade, and looks like it is made of plastic. Under a 10x magnifying glass, the surface of B-grade goods is covered with spider-web-like tiny cracks. C-grade jadeite refers to jadeite and its finished products that have been artificially treated with foreign dyes or drugs. The method is to use high temperature and high pressure to infiltrate the dye into the originally colorless jade, dyeing it completely or partially into emerald green or purple, etc., but its color will fade and darken over time. Please note that if you want to dye it, you must artificially destroy the structure of the jade, otherwise the dye cannot enter the interior. But this destruction is not necessarily pickling. Note: The colors of general C goods are mostly too bright or weird, and they are floating and dull. If you look closely, you may see that the color is concentrated in the cracks. Jade B+C goods: refers to the combination of B goods and C goods, that is, jade products that have been corroded and dyed with strong acid, and then injected with colorless or colored glue. B+C goods look beautiful in appearance, both in color and water content. They are good as inexpensive accessories, but they have no collection value. Note: B+C goods not only have acid etching marks on the surface, but also the color is not correct. In many cases, the color will penetrate into a network along the texture of the jade and pigment will be precipitated. After understanding what A-grade jadeite means, let's now learn how to identify A-grade jadeite: Identification method of jadeite A grade When it comes to jadeite collection and investment, the first thing to consider is "identification", and the first step is to determine whether a piece of jadeite is authentic. It is generally believed that reliable identification of jadeite A, B, and C grades requires comprehensive considerations. Here are some identification features of jadeite A for your reference: 1) Luster: After polishing, the surface of A-grade jadeite is generally smooth, with occasional dents. Overall, it has strong rigid reflectivity and presents a glassy luster. After being soaked in strong acids and alkalis, B-grade jadeite becomes loose in structure, with corrosion pits on the surface, producing a gelatinous diffuse reflection and a pockmarked luster. After being filled with glue, the surface has a resin luster and lacks spirituality. 2) Jadeite: Jadeite refers to the cleavage planes or crystal planes of monoclinic pyroxene in jadeite. The reflection of light appears as flaky, needle-like or star-like flashes. This phenomenon is called "jadeite", also known as fly wings. Generally speaking, the coarser the particles, the easier it is to observe the jadeite texture. However, the "jadeite texture" is usually not visible in microscopic crystalline jadeite, so the "jadeite texture" cannot be used as a characteristic mark of natural jadeite. 3) Color: Grade A jade has natural color and a sense of layers. The color of B-grade jadeite is formed by decolorization of the original color, which is bright and yellowish. Since the structure of jade is destroyed and its original optical properties also change, the color distribution of B-grade jade has no sense of hierarchy and is a chaotic mass of one color. Some C-grade jadeite is dyed all over, some is dyed only partially, and some is also dyed purple (also known as "spring color"). Using a 10x magnifying glass (even obvious with the naked eye), you can see the dark green threads soaked in the micropores. 4) Impurities: When observing under magnification, yellow, brown, and black impurities may be seen on grade A jadeite. Grade B jadeite is relatively pure and has no impurities. 5) Absorption spectrum: Various green jades have typical absorption spectrum characteristics. Emerald green jade must have three obvious absorption lines caused by chromium located in the red light region, and have the so-called step-like characteristics. For green to light green jadeite, the chromium absorption line in the red light region may not be obvious, and generally only the 660nm absorption line can be seen. However, the 473nm absorption line can be seen in the purple light region. It is generally believed that this absorption line is caused by Fe (iron). 6) Ultraviolet fluorescence: The ultraviolet fluorescence effect of jade is an important reference for identifying A, B, and C grade jade. Natural jade generally has no fluorescence, and some of the "white cotton" has light yellow fluorescence. Most B-grade jadeite is filled with organic glue and generally has a blue-white fluorescence (the filled wax also has a blue-white fluorescence). Some B-grade jadeite has no fluorescence and may be filled with silica gel or other substances. Most dyed jadeite on the market currently has no fluorescence (the same as natural jadeite); but some have obvious fluorescence. Certain fluorescence characteristics are very useful for identification, such as a jadeite dyed green that emits a strong yellow-green fluorescence, and a jadeite dyed red that has a strong straw yellow fluorescence. Through the above introduction, I believe you understand what A-grade jadeite means. In fact, to put it simply, A-grade jadeite refers to natural jadeite, not the grade of jadeite, nor does it mean good jadeite. fcgc66 fcpf18 |
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