Comparative Studies On The Nephrites From Four Dirrerent Areas

The nephrites from Xinjiang, Qinghai, Russia and Korea were studied since theconfusion of the origin. The differences of the nephrites were analyzed and a criterionwas proposed forward to identify the nephrites from the four different areas. Thegeneral gemological characteristics, ultraviolet-near-infrared absorption spectrum,chemical composition, mineral composition and microstructure were tested with thehelp of the equipments such as conventional gemological identification apparatus,optical fiber spectrometer, EDS, X-ray diffractometer, infrared spectrometer, scanningelectron microscope and polarizing microscope, etc. The differences of the nephritesfrom the four areas were concluded.It was difficult to distinguish the origin of the nephrites through the routine testsince the general features of them were similar, for instance, gemological parameters,UV-IR absorption spectrum, chemical component, mineral constitute, and so on. Thefour kinds of nephrite can be distinguished from their structure as the main structure ofthem was different. The fiber intertexture crystalloblastic texture was the mainstructure of Xinjiang nephrite and the quality of the nephrite with this structure wasexcellent. A majority of the nephrites from Xinjiang comes with this kind of structure.The nearly parallel fiber crystalloblastic texture was the generally structure found inthe Qinghai nephrite. A great number of the nephrites from Qinghai bears with thestructure of this kinds and the transparency of that was generally high but lack ofmoist, so their quality was medium in general. The microscopic scaly blastic textureand coarse porphyroblast fine crystal structure were commonly found in the nephritesfrom Russia, and the quality of the nephrites was depressed a lot since the existence ofthe coarse porphyroblast tremolite. The main structure of the Korea nephrites wascoarse granular blastic structure, and this structure caused the unique "gruel" texture inthe Korea nephrites.The quality of the nephrites was a greatly influenced by the structure they bornand the component they buildup of. The quality of the nephrites from Xinjiang was the best by reason of the fact that the structure of them was the most delicate and theimpurity was least. The quality of the nephrites from Qinghai was fine although not sogood as that from Xinjiang. As for the nephrites from Russia, the quality was generallybelow that from Qinghai, and that from Korea was in the last.