A Study On Gemology And Genesis Of Dushan Jade In Nanyang, Henan Province, China

As one of the most widely used jade enjoying a long application history Dushan jade plays an important role in Chinese jade culture, and holds a unique position in Chinese colorful and magnificent jade culture. Dushan Jade is indispensable in Chinese gem industry because of its good quality and infrequence. Dushan jade is in a class by oneself in the world with high research and economic value as well as art level. What's more, the deposits, genesis, occurrence and geological characteristics are representational home and abroad. This paper research the mineral combination, petrology characteristic, geological characters, genesis&mechanism and others related to Dushan Jade in details.On the foundation of detailed field investigation, Occurrence of Dushan jade's wall rock of is veins and muti-phases form with prevalent metamorphism process. The cataclasm lithification, mylonite lithification and strong alteration phenomena is observed. At the same time, Dushan jade and its wall rock undertook strong stress, and the minerals were mutil-periodic.The main minerals are plagioclase(indianite), zoisite, hornblende, and the minor minerals were mica, sphene, prehnite,tourmaline, tremolite, calcite, diopside,apatite, opaque iron mineral ( hematite , chromite, pyrites, pyrrhotite ) and so on. But the content of these minerals in the Dushan jade varied with the colors of Dushan jade. Mineralogy analysis cleared about the minerals combination laws in different color Dushan jades. This paper summarized the crystallization order of the minerals in Dushan jade by the view of genetic mineralogy.This dissertation defined the Dushan jade according to broad and narrow sense, put forward the class method integrated with business and local vulgarisms based on the combination of mineral. Those provided scientific basis to restrict and promote the market development of Dushan jade. At the same time, the paper measured the gemological parameters of Dushan jade systemically.The paper firstly utilized the ICP-AES to test and analyse Dushan jade, the result showed that the quantities of main elements and trace elements contained in different colors of Dushan jade are different and the transition metal elements such as Ti, V, Cr,Mn and Fe had strong influence on cause of Dushan jade color. Dushan jade enriched high content of Ba and Sr. And the analysis indicated that Dushan jade was related with mantle original rock showed that Dushan jade came through complex evolvement.The paper discussed the genesis of Dushan jade based on the geological condition, hydrothermal effect, mineralization process and phases. The conclusions were that compositive operations of multi-geographical , especially ductility shear processes resulted in the Dushan jade.The staggered mineralization was because of staggered fractures and pulsant hydrothermal. Different physical-chemical condition and stress effect in every phase made for multicolored Dushan jade veins with different structure and different mineral combination. Research on inclusions indicated that the mineralization temperature of Dushan jade is between 2300C-3300C and belonged to middle-high hydatogenic deposits.