Study Of Mineralogy Characteristics And Jade Formulation Progress Of Qinghai Nachitai Nephrite Deposit

Domestic scholars hold different opinions on the formulating process of Qinghai Nachitai Nephrite and its'material resources of Magnesium.Therefore,this paper applied normal mineralogy characteristics tests,microscope examination,EPMA,XRD power diffraction,FIR Spectra,Raman Spectra and other methods to make researches and analysis on Qinghai Nachitai Nephrite and its'surrounding rock and try to explore the formulating process of it.Qinghai Nachitai Nephrite is white with a slight of cyan,weak oil luster and a lower transparency.Its'RI is about 1.60?1.61.The microhardness is about 798which is about 6.26 in Mohs hardness.The average specific gravity is 2.904.Using gemology microscope to have observation,course grained tremolites in tremolite marble assemble as aggregation or cross with each other.They have no obvious directionality and formulate the grillwork in the three dimension space.While the fine grained tremolite is extremely small and they formulate the micro cryptocrystalline and micro crystallite structure.The nephrite in this deposit have mainly three structures,fabric to column structure,porphyroblastic texture and stretched parallel fabric structure.There is hair structure around the edge of the ore vein.Compared with nephrite produced from other places,tremolite in Qinghai Nachitai nephrite has medium content for Si O₂and higher content for Mg O,Ca O.In the surrounding rock,marble,there are many big and long column,straggling tremlite.The small and fabric tremolite besides the quartz vein formulated the fasciculation structure.Also,there are alteration of lizardite,talc,silicon and so on around the nephrite.The XRD,FIR,and Raman spectra tests show that the main components of Qinghai Nachitai Nephrite are tremolie.According to XRD test,the crystallizing index of Qinghai Nachitai Nephrite is higher than Xinjiang and Russian nephrite.The FIR spectra shows that there are a lot of magnesium and less ferrous ion in nephrite.And the acute degree and relative strength of Raman Spectrum peaks could help to identify the degree of texture of Qianghai Nachitai Nephrite.This paper made the speculation of the mineralization process of Qinghai Nachitai Nephrite as follows:neutral to acid hydatogenic extracted magnesium ion from the basic diabase,reacted with the surrounding rock,and formulate the course grained tremolite and tremolite marble.Multiple late neutral to acid hydatogenic invaded,brought adequate Si and heat,and produced fabric and cryptocrystalline tremolite.Tectonic movement reformed these tremolite and made them into nephrite.Besides the basic diabase,the surrounding rock also provided some magnesium ion for the formulation of nephrite.