Nephrite, that is, tremolite jade, is loved by people because of its softness, delicacy, rigidity, toughness, cleanness and astringency. The evaluation system of nephrite has been improved gradually with the development of jade culture and history for thousands of years. As far as materials are concerned, white with skin is of high value, and the tallow white jade produced in Hotan, Xinjiang is the most precious. However, in recent years, due to the aggravation of mechanized mining, the litter resources in Yushi River Basin in Xinjiang are decreasing and drying up. In particular, many experts of the older generation think that in the past hundred years, there has been no exploitation of lanolin in Xinjiang. Since 2003, the relevant regulations of the state allow all jades with tremolite as the main component to be called "Hetian jade". Therefore, Russia, South Korea, Canada, New Zealand, Qinghai Province, Liaoning Province, Jiangsu Province, Guizhou Province, Guangxi Province, Taiwan region, together with Sichuan Province, which has recently discovered deposits, all tremolite produced in the market appear as "Hetian jade". In particular, Russia, Qinghai and South Korea accounted for more than half of the white jade market. Although Xinjiang white jade, which has dominated the market for thousands of years, is extremely favored in today's market, its monopoly position is not guaranteed due to production problems. In recent years, Xinjiang autonomous region has issued a formal regulation to classify the colors of Hetian jade in broad sense, and lanolin jade has been put on the market again. But at this time, the lanolin jade does not represent "jade out of Hetian", and even breaks the boundary of "jade out of Kunlun". According to the products defined as "lanolin jade" by the relevant departments in Xinjiang, lanolin jade mainly reflects the whiteness of nephrite, with some oil-based and texture requirements. Therefore, regardless of whether the majority of jade lovers agree with it or not, it must be admitted that some white jade produced in Russia and Qinghai can be classified as lanolin white jade according to the current relevant regulations, especially Russian white jade, with a high proportion of lanolin jade. Of course, as far as the quality of jade is concerned, the current "lanolin jade" is still the best in general and tianyuzhong, including Xinjiang nephrite. It is generally believed that Russian and Qinghai nephrites have no raw materials, that is, Russian and Qinghai nephrites have not been transported by water, but this does not mean that Russian and Qinghai nephrites have no skin. In geological age, all exposed rocks will be weathered by natural conditions such as temperature difference fusion, sunlight exposure, precipitation leaching, etc. structural fissures such as joints commonly existing in rocks will lead to infiltration of some foreign materials, especially iron manganese oxides, and white jade can not be avoided. Weathering in dry environment often leads to loose surface structure of white jade, forming a slurry, while water rock reaction often leads to deposition of dark minerals such as iron and manganese in the surface and cracks of white jade. Therefore, white or black leather materials can be seen occasionally in Qinghai and Russia white jade. Although there are some deep skins in Xinjiang, black leather is considered to be one of the characteristics that Qinghai and Russian materials are different from Hetian materials. Recently, the author met a pair of "black skin" white jade bracelets that can reach the "lanolin jade" level. Unfortunately, after testing, "black skin" is made by artificial filling.
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