含重晶石包裹体的石英硬玉岩的宝石岩相学特征及成因初探  

Gemmological,Petrographic Characteristics and Petrogenesis of Quartz Jadeitite with Barite Inclusion

作　　者：陈梓贤 沈雁翱 林哲琼 卢钊浩 李淑玲 周海杰 张颖欣 CHEN Zixian;SHEN Yan’ao;LIN Zheqiong;LU Zhaohao;LI Shuling;ZHOU Haijie;ZHANG Yingxin(National Gemstone Testing Center Co.,Ltd.,Guangzhou 511400,China;Guzhi Assets Appraisal Co.,Ltd.,Guangzhou 511400,China;Guangzhou Quality Supervision and Testing Institute,Guangzhou 511400,China)

机构地区：[1]国家珠宝检测中心(广东)有限责任公司,广东广州511400 [2]广东谷值资产评估有限公司,广东广州511400 [3]广州质量监督检测研究院,广东广州511400

出　　处：《宝石和宝石学杂志》2021年第1期12-19,共8页Journal of Gems & Gemmology

摘　　要：以宝石学和岩石学的研究方法,对一种紫色硬玉岩进行研究,偏光显微镜显示,岩石的系统鉴定为含钠长石石英微晶硬玉岩,同时发现石英中含有柱状、板状、粒状重晶石包裹体。宝石学基础测试和红外光谱测试确定了样品紫色部分为硬玉,白色部分为石英。拉曼光谱确认了石英中的包裹体是重晶石,辅证了偏光显微镜的包裹体鉴定结果。紫外-可见光谱和能量色散型X射线荧光光谱分析结果说明,由锰引起的大致以580 nm黄绿光为中心的500~600 nm最强吸收带是该紫色硬玉岩的呈色原因。基于岩相学特征认为,该岩石是硬玉岩成岩后,压力缓慢降低导致少部分硬玉与石英反应形成微细粒钠长石混杂在硬玉集合体中,吸附有Ba2+的富含SiO2胶体热液沿硬玉岩裂隙侵入,在SiO2胶体聚沉阶段,释放出的Ba2+与SO2-4反应,析出细小且自形的重晶石,被后续晶化的石英包裹,最终形成了石英包裹重晶石呈流动构造状分布于硬玉岩中的罕见现象。A kind of purple jadeitite is studied by gemmological and petrological methods.It was found that in system identification of the rock by polarizing microscope,the sample is albite quartz microcrystalline jadeitite,and the quartz contains columnar,slaty and granular barite inclusions.The purple parts of the sample are jadeite and the white parts are quartzs.Raman spectrum confirms that the inclusions in quartz are barite,which supports the inclusion identification results of polarizing microscope.UV-Vis spectrum and the qualitative analysis results of energy dispersive X-ray fluorescence spectrum show that the strongest absorption band between 500-600 nm,with about 580 nm as the center is caused by Mn,which causes the purple colour of the jadeitite.Based on the petrographic characteristics,it is considered that some jadeite reacted with quartz to form micrograined albite mixed in the jadeite aggregates with the slowly decrease of pressure after the jadeitite metamorphic crystallization,while the SiO2 rich colloidal hydrothermal adsorbed with Ba2+intruded along the fractures of jadeitite.The Ba2+released in the SiO2 colloidal flocculation stage and reacted with SO2-4to form tiny,idiomorphic barite,which were then included by crystallized quartzs,then a rare phenomenon that included in quartzs barite and distributed in jadeite as the form of flow structure in jadeitite.

关 键 词：重晶石 石英 钠长石 硬玉岩 包裹体 

分 类 号：TS93[轻工技术与工程] P631.4[天文地球—地质矿产勘探]