苏纪石的矿物组成与鉴定特征研究

Mineral Components and Identification Characteristics of Sugilite Jade

  • 摘要: 苏纪石是目前珠宝市场上的一种新兴宝玉石材料, 主要通过颜色特征以及经验来鉴别, 其宝石矿物学研究尚属空白。采用偏光显微镜、傅里叶变换红外光谱仪、电子探针及X射线粉末衍射仪对苏纪石样品的矿物组成、化学成分、红外光谱及XRD特征图谱进行了测试研究。结果显示, 苏纪石样品的主要矿物组成为硅铁锂钠石与石英, 分布有少量的长石、绿泥石和褐铁矿等;其中, 硅铁锂钠石呈板条状或隐晶质集合体, 石英呈等轴他形微粒状或不规则团块状、条带状;硅铁锂钠石的化学分子式为K0.94Na2.86Li2.49 (Fe3+1.59Mg1.82) 3.41Al0.22Ca0.26Si11.02O30.00H2O, 其IR特征峰为455, 507, 588, 653, 694, 777, 797, 1 042, 1 123 cm-1, 其主要的XRD谱线为4.323 (100), 4.063 (57), 3.197 (81), 2.863 (51) ;硅铁锂钠石中MnO的质量分数直接影响了苏纪石颜色的深浅, 其IR, XRD特征图谱是鉴定苏纪石的重要特征之一。

     

    Abstract: Nowadays, sugilite jade is an emerging gemstone in jewelry market, which is just identified by its colour with experiences.The gemmological and mineralogical researches of the sugilite jade are few.In this paper, the mineral components, chemical compositions, IR and XRD spectra of the sugilite jade samples are tested by using the polarizing microscope, Fourier transform infrared spectrometer (FTIR), Electron microprobe (EMP) and X-ray powder differaction (XRD) .The results show that the sugilite jade samples mainly consist of sugilite and quartz, with a small number of feldspar, chlorite and limonite.The sugilite is of lath-like or cryptocrystalline aggregates and the quartz is equiaxed particulate or irregular-shaped mass and band.The chemical formulation of the sugilite is K0.94Na2.86Li2.49 (Fe3+1.59Mg1.82)3.41Al0.22Ca0.26Si11.02O30.00H2O, whose IR characteristic peaks are at 455, 507, 588, 653, 694, 777, 797, 1 042, 1 123 cm-1, and XRD diagnostic peaks are at 4.323 (100), 4.063 (57), 3.197 (81), 2.863 (51) .The content of MnO in sugilite could directly influence the colour of the sugilite jade, and the IR, XRD of the sugilite are one of the identification characteristics for the sugilite jade.

     

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