德国宝石级蓝方石的鉴定与谱学特征  

Gemmological and Spectroscopic Characteristics of Haüyne from Germany

作　　者：雷婷[1] 余悠[1] 姜琴[1] 

机构地区：[1]中国地质大学珠宝学院,湖北武汉430074

出　　处：《宝石和宝石学杂志》2014年第2期32-37,共6页Journal of Gems & Gemmology

摘　　要：蓝方石是方钠石族矿物中的一个稀有宝石品种，德国埃菲尔地区产的蓝方石有着非常独特而艳丽的蓝色，近年来被广泛地运用到国际珠宝品牌的高级定制中。本文对来自德国埃菲尔地区的宝石级蓝方石原石及刻面宝石样品进行了一系列常规宝石学测试，并运用能量色散型X射线荧光光谱仪、紫外-可见分光光度计、红外光谱仪及拉曼光谱仪等大型仪器进行测试分析。研究结果表明，蓝方石的折射率为1．50左右，相对密度2．42～2．48，手持分光镜下橙黄区有弱吸收带，长波紫外光下具有中-强的橙色荧光。除了Fe，Cu致色元素以外，不同价态的硫离子根（S3^-，S04^2-，S^2-）也是导致其独特蓝色的主要原因之一。红外光谱在1118、1007、726、700,650、611、540、448cm^-1。处的吸收峰和拉曼光谱在448、545、989、1089和1628cm-1处的吸收峰为蓝方石的诊断性鉴别依据。Hatiyne is a rare gemstone in sodalite group with unique bright blue colour. The authors undertook a series of tests and analyses on gem-quality haiJyne samples from Eifel district in Germany with the help of conventional gemmological tests, energy dispersive X- ray fluorescence spectroscopy, UV-Vis spectrophotometer, Fourier transform infrared spec- trometer and Raman spectroscopy. Conventional gemmological tests show that the refractive index of hatiyne is around 1.50 and specific gravity ranges from 2.42 to 2.48. Weak absorption band at orange region can be observed by a hand spectroscope. Under long-wave ultraviolet light the samples show orange fluorescence of medium to strong intensity, the lighter the colour, the brighter the fluores- cence, and vice versa. It shows that in haiiyne there are many point-like, needle-like inclu- sions, rounded crystals and stress fractures around, fingerprint inclusions and healed frac- tures observed by microscope. The results of energy dispersive X-ray fluorescence spectra of hauyne samples show chromophores as Fe and Cu, which can cause blue colour in gemstones. UV-Vis spectropho-tometer analysis o{ hatiyne samples shows a gentle absorption band at 600--700 nm, and with stronger absorption, the blue colour of haiiyne sample is deeper. In previous resear- ches, electron magnetic resonance spectra of lapis lazuli were studied in order to explain col- our origin, which is also a member in sodalite group. Analyses revealed that the unique blue colour in sodalite group should be attributed to sulfur in their chemical composition, and so is their orange fluorescence under long-wave ultraviolet light. From the testing results and discussion, despite the existence of chromophores like Fe and Cu, different valence states of sulfur ions （S3- ,SO4 ^2- ,S^2- ） are part of the reasons that lead to unique blue colour of hauyne. Since the haiiyne samples obtained are all very small, powder method is used to study the infrared spectra of hatiyne samples. Results show that abso

关 键 词：蓝方石 红外光谱 拉曼光谱 颜色成因 

分 类 号：TS93[轻工技术与工程]