德国宝石级蓝方石的鉴定与谱学特征

Gemmological and Spectroscopic Characteristics of Haüyne from Germany

  • 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,SO42-,S2-)也是导致其独特蓝色的主要原因之一。红外光谱在1 118、1 007、726、700、650、611、540、448cm-1处的吸收峰和拉曼光谱在448、545、989、1 089和1 628cm-1处的吸收峰为蓝方石的诊断性鉴别依据。

     

    Abstract: Haüyne is a rare gemstone in sodalite group with unique bright blue colour.The authors undertook a series of tests and analyses on gem-quality haüyne 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 spectrometer and Raman spectroscopy. Conventional gemmological tests show that the refractive index of haiyne 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 fluorescence, and vice versa. It shows that in haiyne there are many point-like, needle like inclusions, rounded crystals and stress fractures around,fingerprint inclusions and healed fractures observed by microscope.

     

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