In the identification of ancient jade, the color is an important reference. It not only gives the ancient jade a unique color, but also is the key to authenticity. The formation of Baiqin and Caiqin is not only due to the chemicals in the soil, but also closely related to the processing history and burial environment of jade. 
There are different theories about the origin of Bai Qin, some believe that it was due to the high temperature heating carried out by the ancients to facilitate carving, and others believe that it was caused by the burning of jade in some sacrificial activities. The acidity and alkali substances in the soil are also a major influencing factor, for example, the high content of hydrofluoric acid in Yuhang area of Hangzhou has caused serious erosion of Liangzhu culture jade. Weathering also played a key role in the formation of Baiqin, which made the mineral structure of jade loose, and the shape and direction of the crystals changed and pores were formed, resulting in poor light transmittance of jade.
The formation of Caiqin is mainly due to the chromogenesis of iron ions, part of which is the oxidation of iron ions in the jade itself, and part of it is the infiltration of iron oxide in the surrounding environment. The difference in color between red, brown, yellow, and black is due to the difference in iron content. Although there is a belief that the cause of black is related to mercury, the majority of the current opinion is that this is not true.
Some scholars have found through experiments that light-colored tremolite jade can appear brown-black or black when heated to a specific temperature, and it is speculated that the brown-black tremolite jade unearthed from the Fengxi site in Xi'an is caused by high temperature heating. Some scholars believe that it is caused by the heating and carbonization of organic matter infiltrated into the cracks on the surface of the jade, or the infiltration of external iron elements that causes tremolite to transform into actinolite and thus form black qin.
The cause of green is the infiltration of copper oxide. When ancient jade is buried with bronzes, patina will adhere to the surface of the jade, and gradually seep in and form a green stain over time. The composition of this patina includes oxides of bronze alloying elements such as azurite, malachite, and zinc malachite. In short, the cause of ancient jade color is a complex process that involves the combined action of many factors. Players, if there are any additions or corrections. Welcome to share your unique insights in the comment area. It is also possible to enter the topic of literary circles
Participate in the discussion. 
Disclaimer: The article is provided by Yunzhu Zen Heart to organize and publish, part of the content of the article and ** from the Internet, that is, as a reference for learning and exchange. The views expressed in this article are solely those of the author, and I would like to thank the author for his careful preparation. If there is a copyright problem, please contact us and we will remove it as soon as possible).