贵州和田玉的产地标型特征和鉴别初探

Origin Characteristic and Identification of Nephrite from Luodian,Guizhou Province

本文运用宝石学、矿物学的研究方法,借助电子探针、扫描电镜等现代测试技术手段,辅以统计分析方法,对贵州和田玉与其他产地和田玉的标型特征进行对比分析研究。结果表明,贵州和田玉多呈蜡状光泽,略带"瓷感";折射率与其他产地和田玉接近,但密度相对偏低;含有少量透辉石、方解石、石英、斜长石及铁锰质矿物,与其他矿床成因的和田玉明显不同;此外,不同产地和田玉的Na_2O、K_2O、Al_2O_3、MgO、TFeO、CaO、MnO含量有所区别,可利用判别分析法辅助鉴定产地;同时,贵州和田玉的微观结构观察表明其透闪石颗粒更为细小,整体结构更为细腻,多数孔隙度较其它产地和田玉大。

By using gemmological,mineralogical and statistical analysis methods,and modern analytical techniques such as electron probes and scanning electron microscopy,the origin characteristics of nephrite from Luodian,Guizhou and other deposits' nephrite are analyzed.It was found that most of nephrite from Luodian,Guizhou Province has a waxy luster with a slight "ceramic" luster;the refractive index is close to that of standard tremolite,and the density is slightly lower than that of other deposits.Nephrite from Luodian,Guizhou Province contains a small amount of diopside,calcite,quartz,plagioclase and metal minerals,which is obviously different from the nephrite of other deposit types.The contents of Na,K,Al,Mg,Fe and Ca element in different deposits are different as well,and the discriminant analysis method can be used to identify the origin.At the same time,the microstructure of nephrite from Luodian,Guizhou Province also shows that the tremolite particles are finer and the overall structure is more delicate,also the porosity of most nephrite is larger thanthat of other places.