巴基斯坦磷钇矿的宝石学和谱学特征

Gemmological and Spectral Characteristics of Xenotime from Pakistan

巴基斯坦磷钇矿主要发育短柱状晶体,呈深浅不一的黄色,玻璃光泽,透明-半透明。采用常规宝石学仪器并结合红外光谱仪、拉曼光谱仪、紫外-可见光分光光度计,对巴基斯坦磷钇矿进行了常规宝石学和谱学特征研究。结果表明,巴基斯坦磷钇矿折射率为1.718~1.731,一轴晶正旋光性,呈黄色-深黄色中等程度的多色性,长波和短波紫外荧光均为惰性,相对密度为4.41~4.65。其矿物成分是磷钇矿,放大观察可见内部有大量气液包裹体及片状包裹体,红外光谱最强的特征峰在1050~1072 cm^(-1)之间,还存在1181、649、525、408 cm^(-1)附近的特征谱线;拉曼光谱最强的特征峰在998 cm^(-1)处,次强的特征峰在1056 cm^(-1)附近,在200~700 cm^(-1)之间还表现出了很多特征峰;紫外-可见吸收光谱的特征吸收峰多达10余处,最强的吸收峰位于653 nm左右。综合分析认为,特征包裹体、红外光谱、拉曼光谱和紫外-可见光吸收特征是天然磷钇矿的鉴别依据。

The xenotime from Pakistan mainly develops short columnar crystals with different shades of yellow,glass luster,and is usually transparent to semitransparent.By using conventional gemmological instruments,infrared spectrometer,Raman spectrometer,and ultraviolet-visible spectrometer,the gemmological and spectral characteristics of xenotime from Pakistan were studied.The results show the refractive index of 1.718-1.731,uniaxial positive optical character,medium degree of yellow-dark yellow pleochroism,none fluorescence,and relative density of 4.41-4.65.The xenotime mineral contains many gas-liquid inclusions and flake inclusions that can be found through microscopic observation.The strongest characteristic peak of the infrared spectrum of xenotime is between 1050-1072 cm^(-1),and there are 1181,649,525 cm^(-1) and 408 cm^(-1) characteristic lines.The strongest characteristic peak of the Raman spectrum is at 998 cm^(-1),and the second strongest characteristic peak is near 1056 cm^(-1),and there are many characteristic peaks between 200-700 cm^(-1).There are more than 10 characteristic absorption peaks under UV-Visible light,and the maximum absorption peak is around 653 nm.This study shows that the inclusion,infrared spectroscopy,Raman spectroscopy and UV-Visible absorption characteristics are the basis for the identification of natural xenotime.