The green color is the main color on the earth. The jadeite is the green sediment in the stratum below the levee, the essence of green, the soul of the green. After tens of millions of years of smelting, it becomes a kind of green jade, its beauty, rareness and value. Let the jade have the crown of the jewelry.
Many people know very little about the identification of jade. Here, we mainly introduce the basic knowledge about the identification of jade. It is only for everyone to provide reference when purchasing jade jewelry.
Cui nature: When identifying jade raw materials and finished products, pay attention to the plaque-like interweaving structure of the polished spots on the polished surface. In the case of a jade, you can usually see two forms of jadeite vigilance. One is a slightly larger particle. Granular phenocrysts, the other is fibrous crystals intertwined around the phenocrysts. In general, the phenocryst particles in the same jadeite are uniform in size and are top grade.
Stone flower: In a piece of jade, there are usually small clumps, and the white fibrous crystals with poor transparency are intertwined into stone flowers. This stone flower and spot crystal, some are transparent, some are transparent to opaque. Transparent is Top grade, micro-transparent second, opaque is the next product.
Color: The color of jade is uneven. There are white, è—• pink, oil cyan, green onion, green beans, green and dark green, black, etc. on the green emerald. The whole body is transparent green and the emerald is the top grade. The whole body is transparent and the brilliance is the top grade, and the translucent is second.
Gloss: The emerald's luster is bright and translucent, polished and delicate, and has a soft and strong glass luster. The jade has a high density and a high refractive index; it sinks rapidly in tribromomethane, and nephrite is also characterized by such characteristics as serpent jade and grapes. Stone, quartzite jade, etc., are suspended or floated in tribromomethane. The refractive index of jadeite is 1.63 and the hardness is between 6.7 and 7.4.
Inclusion: The black minerals in the jade, the inclusions are mostly melted and combined, the edges of the particles are loose and cloudy, the green is deeper around the black inclusions, and the green is gone with the black. The minerals and jade in the jade The combination of the phenomenon of chemical substances. The person with the ornament of green and black plaque, after long-term wear directly in contact with human skin, the color of the ink will change with the length of time, and will vary from person to person.
Strong water-holding: refers to a drop of water on the surface of the finished jadeite, the water droplets are raised higher, similar to a drop of water in the lotus leaf, dew on the grass tip. In short, the main identification features of jade are: uneven color, green trend Prolonged; strong glass luster with grease; variegated interwoven structure; cool feeling, the color does not change under the Charles mirror.
How to distinguish jadeite grade
A: Jadeite A refers to the natural, unfilled and added color of natural jade jade pieces called A goods.
B: If it is filled with (such as filled with high molecular polymer, etc.) into B goods; B goods are still mineral components are natural jade ingredients, the color is also natural, but the filling of the gum will affect its color after aging The degree of vividness affects the transparency and luster of jadeite.
C: If the additive processing is called C cargo; the mineral component of C cargo is the natural jadeite component. At the same time, it is called B+C cargo after filling and color processing.
Emerald mineral
The composition minerals of jadeite are mainly jadeite in a single pyroxene cluster or other pyroxene minerals (such as chrome jadeite and omphacite) with high jadeite molecules (NaAISi206); the mineral composition of jadeite is considered to be high pressure and low temperature. The product of metamorphism is confirmed by the synthetic experiments of jadeite. If NaAI in jadeite is replaced by Ca, Mg, Fe, Ct, etc., it will be beyond the scope of English components and become other pyroxene. (English, green Pyroxene, diopside, neon, etc.) The jadeite composed of diopside and neon is also called "Gemstone Jade" but it does not belong to jade jade.
For the identification of jade jadeite, the national standard "GB/T16553-1966 jewellery and jade identification" has made more accurate regulations. However, the jadeite in business is larger than the jadeite jade. However, since jade is a polycrystalline aggregate, To determine whether the mineral composition of the jade and jade categories, the more accurate method is the electronic probe image component analysis, but limited by the equipment, the quicker and more convenient is the determination of the differential oil immersion method, as long as a common polarizing microscope and several bottles of refraction Rate immersion oil, the sample obtained is very small, even if the high-grade ring face does not affect its beauty and value.
Emerald color
Emerald green is the treasure of jade, and the green-green perspective is the top grade, and there is a jargon saying that “the color is ten times higher than the priceâ€. Therefore, the jade coloring technology is constantly innovating. In addition to the home red and purple, only Adding green varieties, at least four kinds of green jade appear on the market. The value of green jade, which looks like natural emerald green, is only one to one thousandth of A goods, even lower than B. It will be colorless jade. Dyeing into a bright green jade as a high-end jade sales, so that some consumers suffer greater losses and mental burden.
Early jadeite with chrome salt added color, observed in the Charles filter into red, (natural green calcium aluminum garnet jade also red), a batch of chromium salt dyed hard jade ring face, as early as 1956, the American Gemological Institute found Nowadays, many dyed jadeites do not use chromium salts. The characteristics under the mirror are similar to those of natural jadeite, and the stability is also good. Therefore, the check filter can only be used as a reference. In the past, the dyed jade, the color grade precipitated in the mesh column. In the text, some of the current green jade colors (including some B+C ornaments or flakes) have not seen this phenomenon, so there is no trace of the precipitation of the coloring agent in the crack, so it is not necessarily A cargo. Come, there is a kind of jade bracelet and pendant that is unevenly dyed in light green. It is pretending to be sold in natural jade. This kind of jewelry has soft color, certain transparency (referring to water), no glue injection, 437nm absorption line under the beam splitting is clear, knocking The sound of the sound, the ultraviolet fluorescence characteristics, and the observation of the Charles filter are basically the same as the natural jade. The retail price of the bracelet is generally 500-1500, which is more popular among the general wage earners and tourists. According to the data of many tests, Is using a dye (partially polished chrome Filled in the micro-holes, due to the reflection of the light, the jade of the dyed part is light green. The whole dyeing is dyed, some of them are directly burned, and some are accompanied by purple (also known as "spring". 2. The second dyeing method is a special variety of lavender with a few segments of pale green.
If it is soaked with a solvent such as detergent (add ultrasonic cleaning if necessary), most of the dye can be washed off, but after cleaning, people will leave a faint green color. With a 10x magnifying glass (obviously even with the naked eye) you can see The micro-stained dark green silk in the pores. After dyeing and washing, the color is lighter, but more like natural, there is a greater deception, the average consumer is difficult to identify, some bosses with certain business experience also see A little bit becomes a batch of goods, and they are fooled, and then they are inevitably passed on to consumers. This is also a frequent occurrence. Even professional jewelry inspectors are slightly negligent, and this dyed jade may be issued as a test report for natural jade.
There are many subjects related to jade identification. Here are the elements to contribute to the common sense of jade.
Author: Cheng Weidong
Talc (Talc) is a layered silicate which is a hydrate.
Theory of MgO style chemical formula 3, 4 - SiO2, H2O, and the theory of chemical composition as follows: 31.68% MgO style SiO2 H2O 63.47% to 4.75%, the natural quality of pure talc ore are very few, most associated with other mineral impurities, common associated minerals include chlorite, serpentine, magnesite, tremolite, dolomite, etc.
Talc is often white, light green, microstrip pink, light grey, with impurities the more the color is deeper, even dark grey, black.
Monoclinic crystal system, ore presents flaky, fibrous and dense.
Pearly luster or oily luster, the heating effect of the talc are substantially heated, lose adsorbed water during 120 ~ 200 ℃, 600 ℃ when begin to lose part of the structure of water, until 1050 when the structure all the water out.
The best way to identify talc is to conduct X-ray diffraction analysis or thermal analysis.
Talc
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