Study On The Characteristics Of Secondary Conformation Of Xinjiang Nephrite

Hetian jade is the carrier of Chinese traditional culture, its development andutilization both have a long history. Through the observation and analysis of anumber of secondary conformations of Xinjiang nephrite, such as placer nephrite,Gobi material, mountain water material, we summarize theircharacteristics. And because of its great significance of the placer nephrite, weattach importance to discuss it.Features on the skin include "sweat pores”, sand hole, crack, stony appearanceetc. Inside the skin are stony appearance, impurity, iron flower etc. Somerelationships between them are summarized: diameter of the sweat pore reflects itshost quality: the finer, the better. The sand hole indicates weaker-weathered orsofter minerals inside, for example, appearance of pyrite often produces a hole onthe surface. Stony appearance exists in both inside and outside, it affects the qualitygreatly; if distributed like stars, its homogeneisity would be apparent. Appearanceof crack is not always a bad thing, as bright-color may occur along the cracksurface.Through the modern test methods such as conventional gem testing, polarized lightmicroscopy, electron microprobe, X-ray powder diffraction and infrared spectroscopy,we find the “flesh” is mainly tremolite, the “skin” of it includes diopside and calcite.The component of different color of the "skin" is mainly tremolite and goethite.Through the study of the nephrite and its surrounding rock from Fuguoling andTiantai and Jinshan mining areas, we find that the surrounding rock and the Hetianjade from mountain have the same components like tremolite, chlorite and biotite etc.The Hetian jade from mountain and Hetian placer nephrite have the same componentslike tremolite and diopside etc. The surrounding rock and Hetian placer nephrite havethe same components like diopside and carbonate etc. These same components contactthe Hetian placer nephrite, the Hetian jade from mountain and its surrounding rock well.The above research provides the theoretical basis of Hetian jade for its designand can be used to avoid the defects. It also provides an important basis for thecorrect evaluation of the quality of Hetian placer nephrite. Relationship of “skin” and“flesh” can be used to infer the quality. For example, if there’re white holes orhard minerals on the surface, there may be some white points or impurities, which willseriously affect the value of the nephrite.Through market research and achievements of predecessors, we summarize theoptimization of processing methods and false means of the Hetian nephrite. Accordingto the national standard, the methods are dipping wax and dyeing. But according to themarket samples, the methods are dipping wax, filling and dyeing. People also copyHetian placer nephrite using mountain material or other materials. It can be detected byinspection, infrared spectroscopy, fluorescence amplification reaction tests, which hasa positive significance on Hetian nephrite market.