贵州罗甸玉矿物学及成分特征

Mineralogical characteristics of tremolite and diopside in Luodian,Guizhou Province

本次研究对贵州省罗甸地区产出的玉石进行了矿物学及化学组成的研究。从外观上,罗甸玉可分为白玉、灰白玉、青白玉、青玉及斑点玉。显微镜下观察罗甸玉的结构为纤维状-柱状变晶交织、纤维状-毡状变晶交织、纤维状变晶交织结构,分带现象明显。利用电子探针对白玉、灰白玉、青白玉、青玉及斑点玉中主要矿物角闪石进行分析,结果显示角闪石为钙质角闪石组的透闪石。根据钙质角闪石的Si_Ti变异及成因类型划分投图,样品落入蚀变和交代角闪石区域内。根据单斜辉石中Ca_Mg_Fe组合分类与命名方法判断,得出罗甸玉矿床中产出的辉石主要为透辉石,并有小量次透辉石。

Mineralogical and chemical compositions of jade from Luodian area of Guizhou Province were studied in this paper. According to the appearance,the jade can be divided into white jade,grayish white jade,light greenish white jade,sapphire and speckled jade. The structure of Luodian jade observed under the microscope is fibrous_columnar metacrystal intertexture,fibrous_pilotaxitic metacrystal intertexture,and fibrous metacrystal intertexture, with obvious zonation. The electron microprobe analysis of the major mineral amphibole in white jade,grayish white jade,light greenish white jade,sapphire and speckled jade shows that amphibole is the tremolite in calcic amphibole group. According to the Si_Ti variation and genetic type classification diagram of calcic amphibole,this mineral falls into the area of altered and metasomatic amphibole. According to the combination and genetic classification of Ca_Mg_Fe in clinopyroxene and the nomenclature,It can be known that the pyroxenes from the Luodian jade deposit are mainly diopside with a small amount of sahlite.