辽宁本溪变色萤石的矿物学特征和变色机理研究

Gemological Characteristics and Mechanism of Color Change Effect of Fluorite from Benxi,Liaoning Province

变色萤石是一种在日光和白炽灯下颜色有显著差别的萤石品种,变色萤石稀有珍贵,具有极强的观赏价值。辽宁本溪是我国变色萤石的重要产地。本文以辽宁本溪变色萤石为研究对象,通过基本宝石学测试、拉曼光谱、红外光谱、电子探针、X射线荧光光谱、LA-ICP-MS测试和荧光发射光谱测试,总结了辽宁本溪变色萤石的宝石学特征、变色机理以及荧光特征。变色萤石在日光下呈现深蓝色―灰蓝色,在白炽灯下呈现紫红色。稀土元素、放射性元素的存在对于变色萤石的颜色影响很大,变色萤石在日光下呈现蓝色是Y3+色心、YO2色心、胶体钙色心和2F-色心共同作用的结果。其具有变色效应与胶体钙色心和2F-色心有关。变色萤石中存在磷灰石矿物包裹体。变色萤石在长波紫外灯下发射弱蓝色荧光,但随着温度的升高荧光发射增强,这与杂质元素替代和放射性辐照产生的晶格缺陷有关。本文的结果有利于加深对于辽宁本溪变色萤石变色效应和荧光的认识。

Color-changing fluorite is a species of fluorite that has a significant difference in color under daylight and incandescent light.Color-changing fluorite is rare and precious,and has great ornamental value.Benxi,in Liaoning Province,is an important production area of variegated fluorite in China.In this paper,the gemmological characteristics,color change mechanism and fluorescence characteristic of Benxi color-changing fluorite were summarized by basic gemmological tests,Raman spectroscopy test,infrared spectroscopy test,electron microprobe test,X-ray fluorescence spectroscopy test,LA-ICP-MS test and fluorescence spectroscopy test.Color-changing fluorite appears dark blue to gray-blue under daylight and purplish-red under incandescent light.The presence of rare earth elements and radioactive elements has a great influence on the color of fluorite.The blue color of fluorite in daylight is the result of the combined effect of Y3+chromophores,YO2 chromophores,colloidal calcium chromophores,and 2F-chromophores.Its color change effect is due to the combined effect of colloidal calcium chromophores and 2F-chromophores.Barite and apatite mineral inclusions are in the color-changing fluorite.The metamorphic fluorite samples emit weak blue fluorescence under long-wave UV lamps,but the fluorescence emission is enhanced with increasing temperature,which is related to lattice defects produced by impurity element substitution and radioactive irradiation.The results of this paper are helpful to deepen the understanding of the color-changing effect and fluorescence of Benxi,Liaoning color-changing fluorite.