绿松石伴生矿物纤磷钙铝石-磷锶铝石的鉴定特征

Identification Characteristic of Turquoise Associated Mineral Crandallite-Goyazite

  • 摘要: 近来,市场上出现一种绿松石的伴生矿物,其外观特征与绿松石颇为相似。通过常规宝石学测试、薄片观察、电子探针、X射线粉末衍射分析、红外光谱、拉曼光谱和紫外-可见光谱分析等测试方法对一个相关样品进行了鉴定研究。结果表明,该样品的矿物组成以纤磷钙铝石-磷锶铝石为主,含有一定量的绿松石等矿物。该样品外观呈蓝色,局部蓝绿色,蓝色分布不均匀,主要呈点状、团块状富集,隐晶质结构,密度为2.52 g/cm3,折射率(点测)为1.62。纤磷钙铝石-磷铝锶石的红外光谱主要具有3 585、3 420、3 140、1 320、1 116、1 039、604 cm-1处的吸收峰,拉曼光谱主要具有1 104、1 034、987、612、518、257、185 cm-1处的拉曼峰。而绿松石在红外光谱与拉曼光谱上与其有明显不同。由于该种绿松石伴生矿物鉴定难度较大,除了常规检测的检测手段,还需结合红外光谱、拉曼光谱、X射线粉末衍射分析、电子探针等测试方法综合分析。

     

    Abstract: Recently, a kind of turquoise associated mineral has appeared on the market, which is very similar to turquoise in appearance. The authors studied a relevant sample by means of conventional gemmological tests and the other methods including thin-section observation, electron probe analysis, X-ray powder diffraction, infrared spectroscopy, Raman spectroscopy and ultraviolet-visible analysis, etc.The results showed that the main mineral component of the sample is crandallite and goyazite, as well as a certain amount of turquoise, etc. The main colour of the sample is blue, partially bluish green, and the blue colour is uneven, mainly enriched as dots or lumps. It has cryptocrystalline texture with the density of 2.52 g/cm3, and its refractive index is about 1.62 (point measurement). The infrared spectra of crandallite-goyazite show the main absorption peaks at 3 585, 3 420, 3 140, 1 320, 1 116, 1 039 cm-1 and 604 cm-1, and the Raman spectra of crandallite-goyazite show the main peaks at 1 104, 1 034, 987, 612, 518, 257 cm-1 and 185 cm-1, which are different from those of turquoise. Since it is difficult to identify this kind of turquoise associated mineral, conventional gemmological tests, Fourier infrared spectrometer, Raman spectrometer, X-ray powder diffraction analysis and electron probe analysis should be ultilized comprehensively.

     

/

返回文章
返回