寿山水坑石的矿物成分、内含物及微量元素特征

为研究寿山水坑石的矿物成分、内含物、微量元素及产地特征,采用了红外光谱、X射线粉晶衍射、扫描电子显微镜、激光拉曼光谱、LA-CP-MS等测试方法。红外光谱和XRD测试结果显示水坑石的矿物组成以地开石为主,珍珠陶石、叶腊石、伊利石在部分样品中作为次要矿物存在;XRD图谱显示地开石有序度较低。扫描电镜测试结果显示萝卜纹的矿物颗粒比基质部分细小,呈不定向排列;暗色颗粒状内含物以自形与它形两种形态镶嵌于地开石基质中。拉曼光谱测试结果表明萝卜纹的主要矿物成分为硫磷铝锶石,暗色颗粒状内含物为黄铁矿。LA-CP-MS测试结果显示高山石、水坑石、田黄的微量元素含量有区别,使用判别分析建立三者的判别函数,对未知样品的判别正确率估计值为90.8%。水坑石中轻、重稀土元素分馏不明显,轻稀土元素富集程度较低。水坑石的原生成矿环境为还原环境,萝卜纹和黄铁矿均为原生包裹体。后期环境的差异造成了高山石、水坑石、田黄在微量元素含量上的差别,地下水环境造成了水坑石中轻稀土元素的迁移;这些差异可作为鉴别三者的依据。

Mineral composition, inclusions and trace element characteristics of Shuikeng Stone from Shoushan, Fujian Province

Infrared (IR) spectroscopy, X-ray powder diffractometry (XRD), scanning electron microscope (SEM), laser Raman spectroscopy and LA-CP-MS were used to study the mineral composition, inclusions and trace element characteristics of Shuikeng Stone from Shoushan, Fujian Province. The results of IR spectroscopy and XRD indicate that the main mineral of Shuikeng Stone is dickite, with nacrite, pyrophillite and illite also detected in Shuikeng Stone as accessory minerals. The crystal particle size of the turnip vein is smaller than the particle size of dickite matrix, and the crystal particles are arranged non-directionally. The dark granular minerals with metallic luster exist in two different forms, i.e., euhedral and anhedral, and are embedded in the dickite matrix. The result of Raman spectroscopy analysis indicates that the turnip vein consists of svanbergite, and the mineral composition of dark granular minerals is pyrite. A comparison of the trace element characteristics between Shuikeng Stone, Gaoshan Stone and Tianhuang Stone shows some differences between them. The discriminant criteria of Gaoshan Stone, Shuikeng Stone and Tianhuang Stone are established by SPSS, and the three kinds of samples can be separated by these criteria. The estimated value of discriminant accuracy for a new sample is 90.8%. The difference between LREE and HREE in Shuikeng Stone is not very obvious, and the content of LREE in Shuikeng Stone is not rich. The primary ore-forming environment of Shuikeng Stone was a reducing environment. The turnip vein and the pyrite are both primary inclusions. Secondary environment caused the difference of trace elements between Gaoshan Stone, Shuikeng Stone and Tianhuang Stone. Groundwater environment caused the migration of LREE. These differences can be used to identify the three kinds of Shoushan Stone.