缅甸翡翠中黑色条带的表征研究  

Research of Genesis of Black Bands in Burma Jadeite

作　　者：毛荐[1] 柴林涛[2] 刘学良[1] 范建良[1] 徐佳渊[2] 金之源[2] 

机构地区：[1]华东理工大学宝石检测中心,上海200237 [2]华东理工大学材料科学与工程学院,上海200237

出　　处：《光谱学与光谱分析》2013年第9期2411-2415,共5页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(51102094);上海市大学生创新实践计划项目(S11052)资助

摘　　要：在缅甸矿区发现一种具有黑色条带的翡翠,外观呈现灰黑色至黑色。X射线粉晶衍射物相分析表明,该种翡翠的主要矿物成分为硬玉与少量的绿辉石。扫描电子显微镜观察到该翡翠的硬玉晶粒间隙与张性裂隙中密布着大量细小的黑色矿物包体,拉曼光谱观测到1 582cm-1的特征峰,部分包体同时出现1 346cm-1的峰,表明该矿物包体为石墨,根据其拉曼特征进一步标识为石墨单晶与无定形石墨。这些黑色石墨包体以各种形式结合成尺寸不一的组合,在3 000nm至可见光波长范围区间造成极大的光散射损耗,导致包体密集区域透明度大大降低,形成黑色条带的外观。通过显微观察在样品中还发现两组锆石包体,经拉曼光谱测试证实其结晶度高,未出现明显的蜕晶化,属于高型锆石。A kind of jadeite jade with black bands appeared in the mining area of Burma,which presents a gray-black to black appearance.X-ray powder diffraction analysis shows that the components of the sample are mainly jadeite and a small amount of omphacite.A large number of small,dark mineral inclusions were observed by SEM（scanning electron microscopy）,distributed in the mineral grain gaps and tensional fractures of jadeite.These inclusions show specific peak at 1 582cm^-1,and some of them also show a peak at 1 346cm^-1,indicating that these black inclusions are single crystal graphite and amorphous graphite,based on characteristic Raman spectra.These graphite inclusions forming different types of group lead to great light scattering loss in the range of 3 000nm to visible wavelength resulting in large transparency loss and cause the black band in sample.Two series of zircons were found in the sample by microexamination with high crystallinity and inconspicuous metamictization,as testified by Raman spectroscopy.

关 键 词：翡翠 黑色条带 扫描电子显微镜 吸收光谱 拉曼光谱 

分 类 号：P575[天文地球—矿物学]