新疆拜城红宝石的宝石学特征

Gemmological Characteristic of Ruby from Baicheng,Xinjiang

利用地质学和宝石学方法,结合偏反光显微镜、电子探针、傅里叶红外光谱、紫外-可见吸收光谱等测试研究手段,对新疆拜城近年出产的红宝石的宝石学特征进行系统的测试研究。结果显示,该地红宝石产于云母大理岩中,属于典型大理岩型红宝石矿床。红宝石颜色呈粉红色—玫瑰红色—红色,颜色随Cr质量分数增加,逐渐浓艳,在长波紫外灯下呈强红色荧光。主要矿物包裹体为:方解石、黄铁矿、闪锌矿、硬水铝石及面纱状、针柱状包裹体。红外光谱在官能团区显示1 990、2 121、2 929cm^(-1)处的硬水铝石特征吸收峰,紫外-可见吸收光谱显示典型的Cr谱吸收特征,具有693.9nm强荧光线。Cr_2O_3质量分数为0.11%~0.62%,FeO_T、TiO_2质量分数极低,与国外著名红宝石产地进行对比,该地红宝石具有高Cr、低Fe、低Ti特点,部分样品颜色浓艳、明亮,具有"鸽血红"红宝石特征。

In this paper,we researched the gemmological characteristics of ruby samples produced in Baicheng,Xinjiang by using geological and gemmological methods,polarizing microscope,electron microprobe,Fourier transform infrared spectroscopy and UV-Vis absorption spectroscopy.The ruby produced in mica marble belongs to typical marble-type ruby deposits.The ruby assumes a pink to rose red to red colour,and the colour thickens with the increase of Cr content.All rubies have strong red fluorescence under long-wave ultraviolet light.The main mineral inclusions are calcite,pyrite,sphalerite,diaspore,acicular and veil-like inclusions.The functional region showed 1 990,2 121,2 929 cm-1 diaspore characteristic infrared absorption peaks.In the UV-Vis absorption spectra,the ruby show typical 693.9 nm strong fluorescence band of Cr.The content range of Cr 2 O 3 in ruby is 0.11%~0.62%,while those of FeO T and TiO 2 are extremely low.Compared with the famous ruby origins around the world,the ruby from Baicheng has high Cr content,low Fe and Ti content.Some ruby samples have bright colour and show strong fluorescence characteristics of“pigeon’s blood”ruby.