According to its composition, occurrence and other characteristics, the outer skin of Puyu can be divided into three categories: colored skin, sugar skin and stone skin.
Color skin: A layer of jade skin distributed on the surface of Hetian Ziyu has various colors. The jade world is named after various colors, such as black leather, deer skin, etc. From the color of the leather, we can see the quality of the jade, such as black leather, deer skin, etc., which are mostly high-quality white jade. The sub jade of the same quality, such as those with the skin color of autumn pear, has higher value. The thickness of jade skin is very thin, generally less than 1mm. The color skin has various shapes, some of which are cloud like, some are vein like, and some are scattered. The formation of color skin is caused by the transformation of ferrous oxide in Hotan Jade into ferric oxide under oxidation conditions, so it is secondary. Experienced jade collectors should go to the middle and lower reaches to find colored jade; However, there are few opportunities to find colored leather jade upstream. In addition, hill materials with skin can be occasionally found near the fractures of the primary jade ore body, which is also due to secondary oxidation.
Sugar skin: refers to a layer of yellow brown and soy colored jade skin distributed on the surface of Hotan Jade Mountain. Because the color is like brown sugar, the jade with sugar skin is called sugar jade. The thickness of sugar crust of sugar jade is relatively large, ranging from a few centimeters to 20-30 centimeters. It often surrounds white jade or sapphire, showing a transitional relationship. Sugar jade is produced near the fissure of ore body. Sugar jade is the product of oxidation environment. After the formation of Hotan jade, residual magmatic water permeates along the cracks of Hotan jade ore body, transforming ferrous oxide into ferric oxide. Sugar skin is the result of iron oxide staining.
Stone skin: refers to the surrounding rock surrounded by Hotan Yushan materials. One kind of wall rock is tremolite dolomite marble, which is mined together with jade and attached to the surface of jade when it is re mined. This jade coated stone has a clear boundary with jade and can be separated. When it is washed and transported by flowing water or glacier for a long time, stone and jade are separated. The other type of wall rock is tremolite. For example, in the process of the re formation of Hotan Jade, coarse crystal tremolite was replaced. Due to incomplete replacement, coarse crystal tremolite is often attached to the surface of the jade, which is a transition between the stone skin and the jade. It is called yin and yang surface. The yin surface refers to the stone like appearance of jade.
The purchase of Hetian white jade can be roughly judged from the following perspectives: first, check whether the whiteness grade is enough, and then check whether the moistening degree of the jade liquid is enough, that is, whether the jade quality is exquisite, and the proportion of waterline is only one or two. There is no problem. The proportion of jade flowers, the number of impurities, and whether there are cracks on the jade surface. If you like the color of the jade, finally check whether the jade is beautiful, the autumn pear skin, the jujube skin, the deer skin Sajinpi~~~These are all precious varieties of Hotan Jade, but you should prevent fake leather. Having basically mastered these principles, I believe you will choose a good jade.
