1, gloss. After soaking in strong acid and alkali, jadeite has loose structure, and there are pits on the surface before it is full, which makes it spread and its luster weaken. After adding organic fillers such as resin or plastic, jadeite often appears resin luster or wax luster, or glass luster mixed with resin luster and wax luster.
2. color. Because the structure of jadeite has been destroyed, the original optical properties have changed, and the color distribution of jadeite in the expansion of B goods has no layering. Although the green color of jadeite treated by this method is still the original color, after soaking in acid solution, the background color turns white, the green distribution floats, and the orientation of the original color is also destroyed, which looks unnatural.
3. structure. After the jadeite is corroded by strong acid and alkali, some substances are brought in and out, and corrosion is formed on the surface and inside along the mineral crystal, resulting in internal connected cracks. Under the irradiation of transmitted light, we can see the crisscross cracks inside. Under the condition of reflected light, the corrosion pits or cobweb network structure on the surface are clearly visible.
4. Surface features. The hardness of jadeite treated by this method is quite different from that of jadeite itself. There are obvious gullies in the primary cracks, and the fillings are obviously lower than those on both sides. Many cracks form crisscross gullies. "The surface of jadeite bleached and filled by better processing technology is very smooth, and there is no such phenomenon, which needs more careful observation and judgment.
5. Density and refractive index. Most jadeites that have been bleached and filled have slightly lower density and refractive index. However, due to the complex mineral composition of jadeite, the density and refractive index of some natural jadeite may be low, so the density and refractive index can only be used as reference data, and usually cannot be used as a basis for judging whether jadeite is filled.
6. Fluorescence. There is no or weak strong ultraviolet fluorescence, and the fluorescence distribution is uniform or patchy. Most of the early "B-goods" jadeites have fluorescence. Short wave: weak, yellow-green or blue-green; Long wave: medium to strong, yellow-green or blue-white. However, jadeite treated by this method usually has weak fluorescence intensity or no fluorescence.
7. Magnification inspection method. Magnification test is an effective method to treat jadeite. Divided into surface observation and internal observation.
8. Thermal reaction. The colloid of "B" grade jadeite is carbonized after heating at 200 ~ 300℃.
9. Knock reaction. After bleaching and filling, the structure of jadeite is destroyed and mineral particles are filled with colloid. Therefore, it will make a dull sound after tapping, which is obviously different from the crisp sound of natural jade.
Extended data
Reasons for the formation of jadeite
Jadeite is a dense and massive aggregate formed by countless fine fibrous mineral crystallites, mainly jadeite. There are four main views on the formation of jadeite in nature:
The first view is that it is the desilication product of residual granite slurry that magma intruded into ultrabasic rocks under high pressure.
The second view is that primary albite is decomposed into jadeite during regional metamorphism; Or that albite first formed glaucophane schist with low metamorphic degree and then further metamorphic jadeite under the action of compressive and torsional stress and low temperature caused by plate collision.
The third view holds that granite veins and light gabbro veins were formed by metasomatism under the pressure of 12 ~ 14 kPa under the action of hot water solution with high sodium chemical potential.
According to the discovery of water-methane-jadeite three-phase inclusions in jadeite rocks, the fourth view is that jadeite is crystallized from the silicate melt of jadeite, which comes from the alkali-containing pyroxene layer widely existing in the mantle of 300 ~ 400 km.
Classification of jadeite jade
1, goods a (allowed)
The A product of jadeite is natural jadeite, which is naturally produced. It is only processed, carved, polished and polished by physical methods, and its internal structure has not been damaged by any chemical or irradiation methods.
The new A product only adds color to the color root on the basis of A product jade. It is particularly important to note that this jadeite colored product has no fluorescence reaction and does not change its specific gravity. "Emerald A Certificate" will be issued by lax appraisal agency. This kind of jadeite is sold in the jewelry market and even in many famous shops. If you buy jade with collectible value, remember to be cautious.
2. Commodity B (bleached and polymer embossed jade)
Pickling, bleaching and glue injection treatment
3. Goods C (coated jade)
Dyeing treatment. Used for jadeite dyeing. Whether it is acid leaching bleaching or filling with glue, artificially colored jadeite is called C goods.
The famous origin of jadeite:
Most of the high-quality jadeites in the jewelry market come from the Quaternary and Tertiary conglomerate layered jadeite deposits in the Ulu River basin of Myanmar. They are mainly distributed in the mountainous areas of northern Myanmar, with a length of about 240 km from north to south and a width of 170 km from east to west.
187 1 year, primary jadeite deposits were discovered in Lu Wu river basin, Myanmar, among which the most famous deposits are Dumao, Myanmar, Panmao and Nannaimao. Primary jadeite is mainly composed of white jadeite with various green tones, brownish yellow and light purple. In addition to jadeite, there are diopside, amphibole, aegirine and albite, and green jadeite rarely reaches the gem level.
References:
Baidu encyclopedia-emerald