A Study On The Mineralogical Characteristics Of Diorite Bearing Jades In Hanzhong,Shaanxi Province

In this paper,the gemmological properties,chemical composition,internal structure and spectral characteristics of the tremolite jade in Hanzhong,Shaanxi Province were studied by means of Gemmological tests,polarizing microscope,scanning electron microscope,electron probe,X-ray powder diffraction,UV-V is absorption spectrum,infrared spectrum and laser Raman spectrum.Tremolite jade is mainly light blue and light blue-green,with glass luster grease luster,micro transparency opaque,crystalline aggregate,good integrity and undeveloped fracture;its relative density is between 2.6594 and 2.8038,and its Mohs hardness is between 5.04 and 5.13.The surrounding rock is gray white light blue serpentine tremolite dolomite marble and brown quartz diorite.The electron probe test results show that the main mineral composition of tremolite jade is tremolite,dolomite,serpentine,calcite,etc.the surrounding rock contains talc,quartz,albite,chlorite,iron oxide and other minerals.X-ray powder diffraction shows that the main mineral components of jade samples are tremolite,dolomite,calcite and serpentine.The tremolite in tremolite jade is observed by polarizing microscope There are four kinds of microstructure,which are micro felt structure,micro radial structure,micro fiber structure and micro column structure.It is found by SEM that tremolite has micro fiber structure,micro flake structure and micro fiber interwoven structure.The UV-V is absorption spectrum shows that the tremolite jade sample has strong absorption near 448 nm.It is analyzed that the tremolite jade is caused by Fe²⁺.The sharp absorption spectrum near 3678cm^-11 is caused by the antisymmetric stretching vibration of M-OH in tremolite;the absorption peak near 998 cm^-11 is caused by the antisymmetric stretching vibration of o-si-o,the antisymmetric stretching vibration of Si-O-Si and the symmetric stretching vibration of o-si-o.in addition,the absorption bands near 1430 cm^-11 and 876 cm^-11 are also shown,which are caused by the antisymmetric stretching vibration of o-si-o and the antisymmetric stretching vibration of si-o-The antisymmetric stretching vibration and out of plane bending vibration.The Raman spectra show that the strong Raman displacement of calcite minerals near 1087cm-1 is caused by[CO₃]^2-symmetric stretching vibration,and the strong Raman displacement of tremolite at 675 cm^-11 is caused by Si-O-Si symmetric stretching vibration.The orebodies of tremolite jade are mainly layered,lenticular and veined,and their boundary with surrounding rock is fuzzy,the tremolite jade deposit has the characteristics of magmatic hydrothermal control and stratigraphic control.The formation temperature of chlorite is 224?,which is in the range of hydrothermal alteration.Therefore,it is believed that the genesis of amphibole jade in Hanzhong is a hydrothermal metasomatic deposit.