老挝华潘华勐红宝石的宝石学及谱学特征

Gemmological and Spectral Characteristics of Ruby from Huameuang, Houaphanh Province, Laos

  • 摘要: 老挝有着矿产资源丰富的“T”型成矿带,其关于刚玉的开采历史可追溯到20世纪90年代,但目前只有针对老挝会赛玄武岩型蓝宝石的相关研究,国内外暂无对老挝红宝石的相关研究文献记载。以老挝华潘华勐红宝石样品为研究对象,采用常规宝石学测试、傅里叶变换红外光谱仪、紫外-可见-近红外光谱仪和激光剥蚀等离子质谱仪等测试仪器对老挝红宝石样品展开系统性的基础研究。结果表明,老挝红宝石样品的颜色带紫色调,部分样品可见不规则色带和蓝色色区;内部裂隙及裂理发育,拉曼光谱测得其内部含方解石、金红石、白云母等固体包裹体和气液两相包裹体,透明度较差;主要致色元素为Cr、Fe和Ti,具有高Cr低Fe的特征,为典型的变质岩型矿床;红外光谱中除Al-O本征吸收峰,还出现明显的1 982、2 122、2 924 cm-1处的硬水铝石特征吸收峰;拉曼光谱存在7个振动峰,主要由AlO6基团的弯曲振动和伸缩振动引起。利用微量元素Mg、V、Ti、Fe和Ga的质量分数配比关系,可初步将老挝红宝石与其他产地红宝石进行区分。

     

    Abstract: Laos, a landlocked country, has a "T" type metallogenic belt rich in mineral resources, and its mining history of corundum can be traced back to the 1990s. However, there are only relevant studies on Huay Xai basalt sapphires in Laos at present, and there is no relevant literature on rubies in Laos at home and abroad. In this paper, the rubies from Laos were systematically studied using conventional gemmological test methods, Fourier transform infrared spectrometer, UV-Vis-NIR spectroscopy, LA-ICP-MS etc. The results showed that the colour of rubies from Laos are purple, irregular colour bands and blue zone can be seen in some samples.The internal cracks and cleavages are densely developed. The solid inclusions such as calcite, rutile, muscovite and two-phase fluid inclusions were detected by Raman spectrometer and the transparency is poor. The main chromogenic ions are Cr, Fe and Ti. It is a typical metamorphic deposit with high Cr and low Fe. In addition to the intrinsic absorption band of Al-O, the characteristic absorption peak of diaspore at 1 982, 2 122 cm-1 and 2 924 cm-1 also appeared in the infrared spectrum. There are 7 vibration peaks in Raman spectrum, which are mainly caused by bending vibrations and stretching vibrations of AlO6. According to the mass fraction ratio relations of Mg, V, Ti, Fe and Ga, rubies from Laos can be preliminarily distinguished from other deposits.

     

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