越南安沛红宝石的宝石学及谱学特征

Gemmological and Spectral Characteristic of Ruby from Yen Bai, Vietnam

  • 摘要: 东南亚一个具有重要经济价值的红宝石矿床位于越南北部安沛(Yen Bai)的Luc Yen附近。选用越南安沛大理岩型红宝石为研究对象,根据颜色特征分为4大类:浅紫红色、紫红色、深红色及橙红色。采用常规宝石学测试及X射线荧光能谱仪、傅里叶变换红外光谱仪、激光拉曼光谱仪、紫外-可见分光光度计等测试技术,对越南安沛红宝石进行宝石学特征和谱学特征的综合分析。结果表明,越南安沛红宝石晶体呈典型的板柱状,显微镜下常见丰富的气液包裹体,部分样品可见越南红宝石特征的蓝色色区。红外光谱显示红宝石的5个本征峰,部分样品可见由O—H基团伸缩振动引起的硬水铝石吸收峰。拉曼光谱主要由AlO6基团的弯曲振动和伸缩振动引起。结合成分分析和紫外-可见吸收光谱,通过量化红宝石颜色的主波长、补色主波长及纯度值,可将越南安沛红宝石的4类主要颜色区分开。

     

    Abstract: One of the ruby deposits of important economic value in Southeast Asia is located near the city of Luc Yen, Yen Bai, North Vietnam. Ruby samples were collected in local deposits associated to marble from Yen Bai, Vietnam. According to the colour characteristics, the samples were divided into four categories:Light purplish red, purplish red, dark red, and orange. In this paper, the authors studied the gemmological and spectral characteristics of ruby samples from Yen Bai by conventional gemmological tests, EDXRF, Fourier transform infrared spectroscopy, Raman spectroscopy, and ultraviolet-visible spectrometry. The results indicated that the rubies belong to marble, which show a typical crystal form of hexagonal tabular. Besides, the variety of fluid inclusions ould be observed by microscope, and some samples show the typical single blue zone of ruby from Vietnam. It shows the five intrinsic infrared absorption bands of ruby, and some are ascribed to O-H stretching vibration. Raman bands are mainly associated with the bending vibrations and stretching vibrations ofAlO6. Based on UV-Vis spectroscopy in combination with the component analysis, the four main colours can be separated by quantifying dominant wavelength, complementary dominant wavelength, and colour purity of the rubies from Yen Bai, Vietnam.

     

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