含云雾状包体钻石的宝石学和红外光谱分析

Gemmology and Infrared Spectroscopy Analysis of Diamond with Cloudy Inclusion

钻石中的呈一定对称性的黑色云雾状包裹体是一种很特殊的包裹体,一直以来被认为其中富含H元素。本文中对未知产地含有黑色和黄色的云雾状包裹体的13颗钻石薄片样品进行宝石学和红外光谱学分析。宝石显微观察结果表明,云雾状包裹体主要呈现两种颜色和三种类型的分布特征。包裹体颜色为黑色和黄色;云雾状包裹体呈现几何形状的四次对称、三次对称和环状分布特征。显微红外光谱测试分析表明:(1)所有测试样品均有1 282cm^(-1)的红外光谱吸收峰,指示了钻石均为IaA型钻石;(2)对比空白、黑色和黄色部分红外光谱特征,相比白色部分,黑色和黄色部分具有更强的3 107cm^(-1)吸收峰;(3)不同标本的同种颜色区域红外谱图发现吸收峰峰位存在差异;(4)云雾状包裹体颜色的深浅与红外吸收峰3 309、3 238、3 143、3 107cm^(-1)的强度呈正相关,并与H的存在紧密相关。本研究中可以得到如下结论:钻石中出现的这类黑色包裹体和黄色色块中都检测富含H元素,在结构上主要以C-H和H-OH这两种形式存在^([1])。H在钻石中大量聚集会影响钻石的美观程度和商业价值。H在钻石中的红外吸收谱图有至少以下两种形式。第一种为:3 309、3 238、3 153、3 143、3 107、3 051、2 788cm^(-1)的组合吸收;第二种为:3 236、3 153、3 107、2 788cm^(-1)的组合吸收。这两种均有3 236、3 153、3 107和2 788cm^(-1)的吸收。

The symmetry black cloud inclusion in diamonds is a very special kind of inclusion,which has been thought to be caused by H.In this paper,13 diamond slices containing black and yellow cloud-like inclusions from unknown origin were analyzed by gemmological and IR spectroscopy.The microscopical observation shows that the colour of the inclusions can be black or yellow,and the cloudy inclusions exhibits fourfold and threefold symmetry and annular distribution.The micro-infrared spectroscopy analysis shows that:(1)All the samples tested have an infrared spectral absorption of 1282 cm^(-1),indicating that all diamonds are IaA type diamonds.(2)Comparing the infrared spectrum characteristics of the colorless,blackand yellow parts,the black and yellow parts have a stronger absorption of 3 107 cm^(-1).(3)the infrared spectra of the same colour area of different specimens showed differences in absorption peak position;(4)the colour depth of cloudy inclusion was positively correlated with the intensity of infrared absorption in 3 309,3 238,3 143 and 3 107 cm^(-1),and was closely related to the presence of H.In this study,it can be concluded as follows:cloudy inclusions in diamonds showed H-related IR bands,mainly consistent with C-H and H-OH vibrations[1].The large concentration of H in the diamond will affect the beauty and commercial value of the diamond.The first is combined absorptions of 3 309,3 238,3 153,3 143,3 107,3 051 and 2 788 cm^(-1).The second is the combined absorption of 3 236,3 153,3 107 and 2 788 cm^(-1).Both of these have 3 236,3 153,3 107 and 2 788 cm^(-1) absorptions.