辽宁桓仁夕线石玉的宝石矿物学研究

Gemological and mineralogical characteristics of sillimanite from Huanren in Liaoning Province

近来实验室收到几块外观与和田玉极为相似的玉石样品,为了更好地鉴别该玉石,采用常规的宝石学测试、薄片分析、化学全分析、红外光谱分析、X射线粉晶衍射分析、拉曼光谱分析等方法对其进行了测试研究。结果表明,该玉石样品的主要矿物组成是夕线石,并含有少量的云母和高岭石,其结构为柱状纤维变晶结构,主要呈柱状、纤维状、毛发状分布,样品呈黑色的原因可能与晶格中Fe^(3+)替代Al^(3+)有关,Fe^(3+)含量越多颜色越深。

Recently,the laboratory received a few pieces of jade samples whose appearance is very similar to that of nephrite.In order to better identify this kind of jade,the authors studied it by using conventional gemological methods and other methods such as thin section analysis,chemical analysis,infrared spectroscopy,X-ray diffraction analysis and Raman spectroscopy analysis.The results show that the main mineral composition of this jade is sillimanite,with a small amount of biotite and kaolinite.Its structure is prismatic and fibrous crystalloblastic texture distributed mainly in prismatic,fibrous and hairy forms.The black color of the sample may be caused by substitution of Fe^(3+) for Al^(3+) in the lattice.The more the Fe^(3+) content,the darker the color.