新疆软玉、辽宁岫岩软玉的XRD及红外光谱研究

摘要

选取新疆和辽宁岫岩两地不同颜色的软玉，青玉、黄玉、白玉、碧玉及岫岩的特殊品种---河磨玉作为研究对象，通过宝石学测试、红外吸收光谱和X粉晶衍射分析对两个产地不同种类及颜色软玉的宝石矿物学特征进行了系统研究和对比，以探索两产地相近颜色软玉的异同，为软玉的产地鉴别提供理论依据。研究结果表明，辽宁岫岩与新疆软玉的宝石学性质相似，折射率为1.60～1.62，密度为2.660～3.020 g · cm -3，密度随颜色的不同有一定差异，荧光特征均不明显，两产地软玉的主要组成矿物均为透闪石，其中新疆碧玉中含有少量绿泥石、伊利石等粘土矿物。两产地不同种类软玉的X粉晶衍射分析显示，不同种类软玉的衍射峰峰形特征及衍射强度在一定程度上可以反映软玉的质地及结晶颗粒大小。红外吸收光谱显示两产地软玉的红外吸收光谱特征类似，对鉴别软玉产地及种属意义不大。%The nephrite species with different colors from Xinjiang and Xiuyan ,Liaoning ,including gray nephrite ,yellow neph-rite ,white nephrite ,jasper and He-Mo nephrite ,a special nephrite from Xiuyan ,were selected for the present study .The ge-mological testing method ,infrared absorption spectroscopy and X-ray powder diffraction were used to analyze and compare the gemological characteristics of the nephrite with different colors and textures from the above localities ,in order to understand the similarities and differences between these nephrites with similar colors but different origin ,and provide a theoretical basis for the identification of the nephrite origin .The results show that the nephrites from Xinjiang and Xiuyan ,Liaoning province have simi-lar gemological properties .They have similar refractive index of 1.60~1.62 and density of 2.660~3.020 g · cm -3 ,and only the density has some differences with different colors .The fluorescence characteristics are not obvious in these nephrites .The major constituent minerals for these nephrites are tremolite ,and small amounts of clay minerals such as chlorite and illite are found in the jasper from Xinjiang .Based on the X-ray powder diffraction analysis on the different types of nephrite from two localities ,it was shown that the character of spectra peaks and diffraction intensity of different types of nephrite can reflect the texture of the nephrite and the size of crystalline particles to some extent .The infrared absorption spectra are similar for the nephrites from two localities .The infrared absorption spectrum does not make sense to identify the origin and species of neph-rites .