福建寿山石的矿物学研究.doc

福建寿山石的矿物学研究 【中文摘要】福建寿山石因质地晶莹、凝脂如玉、色彩斑斓,在国内外享誉盛名,主要分布于福州市北郊的寿山、日溪、宦溪乡镇的山村之间,赋存于晚侏罗纪及白垩纪中酸性火山岩中。对寿山石进行的矿物学研究可以为其开发利用提供宝石学数据和资料。本文采用偏光显微镜、扫描电镜、电子探针、X射线粉晶衍射、红外光谱和热分析等现代测试技术方法对采自福建都陵、善伯、虎口、旗降四个矿点的寿山石矿物成分、物理性质、结构构造以及主要矿物成分高岭石类矿物的内部晶体结构等进行了研究。偏光显微镜、扫描电镜、电子探针研究表明都陵石和善伯石的主要矿物成分为高岭石类矿物;虎口石主要矿物成分为叶蜡石;旗降石则由高岭石类矿物和叶蜡石组成。四个矿点的寿山石矿均含有次要矿物石英,少量褐铁矿;而在善伯石和虎口石中还分别含有少量黄铁矿和金红石。通过X射线粉晶衍射研究显示虎口石和旗降石中的叶蜡石分别为1Tc型和2M1型叶蜡石;都陵石和善伯石中的高岭石族矿物以迪开石为主。旗降石的衍射图谱中既有高岭石的“山”字形三连峰也具备迪开石的特征衍射峰,推测为高岭石迪开石混层矿物,其中003、 13 1和131三连峰呈现“中、强、弱”的特点。用Hinckley结晶指数法估算的旗降石、都陵石、善伯石中高岭石类矿物的结晶度指数分别为1.220、1.034、1.057,结晶度差别不大。红外光谱、差热热重分析也证实了四个矿区的矿石的主要矿物种属。根据红外光谱3700～3600-1范围内OH振动谱带的位置和相对强度区分高岭石类矿物迪开石都陵石、善伯石和高岭石迪开石混层矿物旗降石,并计算旗降石、善伯石、都陵石有序度指数OI分别为1.041、0.886、0.995,这与其HI结晶度指数相对应,有序度依次降低。差热曲线吸热谷峰形态的变化在一定程度上反映了矿物结晶度、有序度的变化。; 【Abstract】 The Shoushan stone is of great reputation at home and abroad for its sleek texture, flowery color and various category. The ore are located in the intermediate-acid volcanic rocks of the Late Jurassic and the Cretaceous period around the hills and villages of Shoushan、Rixi、Huanxi which stauated in north of City Fuzhou. The mineralogy study on the Shoushan stone can provide more gemmoloy dates and ination to its exploitation and appliance.Samples collected from four major deposites of Shoushan stone Dulin/Shanbo/Hukou/Qijiang in Fujian Province. were studied by optical microscopyOM, scanning electron microscopySEM, Electron probe analysisEP, X-ray powder diffractionXRD, infrared spectroscopyIR, differential thermal analysisDTA, and thermogravimetryTG in physical characteristics; mineral constituent; conation and internal structure of the main constituent kaolin minerals.The results of OM and SEM in combination with EP analyses determine that Dulin stone and Shanbo stone contain kaolin minerals as a dominant constituent; Hukou stone mainly consist of pyrophyllite, while these two kinds of minerals make up Qijiang stone as the primary compositions. All of these Shoushan stone associated with minor quantities of quartz and little limonite; and little pyrite and rutile exist in Shanbo stone and Hukou stone respectively.The analyses of XRD indicated the prophyllite in stones exist two polymophs, i. e. monoclinic of Qijiang stone and triclinic of Hukou stone; both Duling stone and Shanbo stone are composed of dickite. XRD patterns of QJ stone showed the existence of well-crystallized minerals in which the 003、 13 1、131reflections appeared as medial/intense/weak intensity relationship associated with several characteristic reflections of dickite. These patterns suggested the presence of an intermediate member between well-crystallized dickite and well-crystallized kaolinite. The”Hinckley-type index”of stones from Qijing/Shanbo/Duling is 1.220、1.034、1.057 separately with only a little bit difference.IR and DTA-TG date agree with those from XRD. Dickite of Duling stone and Shanbo stone different from kaolinite-dickite mixed-layer mineral are shown by the position and the relative intensities of the absorption bands in the OH-stretching region 3700-3600cm-1. According to their values of HI, order indexOI of stones from Qijing/ Shanbo/ Duling are 1.041、0.886、0.995 respectively with declination of order degree. The shape and peak temperature of the main endothermic dehydroxylation peak in the DTA curves also reflected differences in crystallinity and order degree to a certain extent.