一种与尖晶石共生的无色蓝宝石的宝石学特征

Gemmological Characteristic of Spinel Associated Colourless Sapphire

利用X射线荧光光谱仪、拉曼光谱仪、荧光光谱仪对一种与紫色尖晶石共生的无色蓝宝石样品进行详细宝石学特征研究。结果显示,该蓝宝石样品中Al_(2)O_(3)含量为99.56%,含一定量的SiO_(2)、CaO、TiO_(2)、Fe_(2)O_(3)、Ga_(2)O_(3)等;拉曼光谱测试显示无色区域为蓝宝石,紫色区域为尖晶石;包裹体为不规则及规则六边形固体石墨包裹体、气体CO_(2)包裹体、含CH_(4)的液体包裹体、愈合裂隙等;荧光光谱测定确定无色和紫色基底区域基本无荧光,发光物质荧光中心峰位于440 nm和460 nm附近,且随着激发波长由365 nm到390 nm的变化,发光中心发生红移,440 nm处荧光中心对于460 nm荧光中心相对强度由强到弱变化。

The gemmological characteristics of a kind of sapphire that is associated with purple spinel were studied by EDXRF,Raman spectrometer,and fluorescence spectrometer.The sapphire sample contains 99.56%of Al_(2)O_(3)and a certain amount of SiO_(2),CaO,TiO_(2),Fe_(2)O_(3),Ga_(2)O_(3),etc.Raman spectra showed that the colourless region is sapphire and the purple region is spinel;the inclusions are irregular and regular hexagonal solid graphite inclusion,gas inclusion that contains CO_(2),liquid inclusion that contains CH_(4),healing crack,etc.Fluorescence spectra showed no fluorescence in the colourless and purple substrate,and the peak positions of the fluorescence center of the luminescent part were near 440 nm and 460 nm.With the change of excitation wavelength from 365 nm to 390 nm,the red shift of the fluorescence center occurs.The relative intensity of the fluorescence center at 440 nm and 460 nm changed from strong to weak.