阿富汗石的宝石学特征及谱学特征  

Gemmological Characteristic and Spectroscopy Feature of Afghanite

作　　者：徐速 石小平 廖俊 XU Su;SHI Xiaoping;LIAO Jun(National Gold-Silver,Gem&Jewelry Quality,Supervision&Inspection Center(Sichuan),Chengdu 610000,China)

机构地区：[1]国家金银珠宝饰品质量监督检验中心(四川),四川成都610000

出　　处：《宝石和宝石学杂志》2020年第1期26-32,共7页Journal of Gems & Gemmology

摘　　要：利用常规宝石学测试方法,紫外-可见光谱仪、红外光谱仪、激光拉曼光谱仪、X射线粉末衍射仪等对阿富汗石样品的矿物组成、紫外-可见光谱、红外光谱及拉曼光谱等谱学特征进行研究。结果显示,阿富汗石样品的折射率为1.523~1.529,摩氏硬度5~6,受S^3-、S^2-分子离子根影响,在长波紫外光下呈弱至强亮橙黄色荧光,紫外-可见光范围内具有600 nm附近吸收宽带和380 nm附近弱吸收带为特征的吸收光谱。红外测试结果显示,指纹区以1005、1119 cm^-1处强吸收峰,伴随1166 cm^-1处肩峰和768、1387 cm^-1处弱峰,及690~400 cm^-1范围内一系列锐锋为特征,官能团区以1631、3438 cm^-1为中心的吸收带为特征。激光拉曼光谱分析结果显示,阿富汗石样品的特征拉曼位移峰位于260、426、453、542、579、615、989、1083 cm^-1,X射线粉末衍射分析显示阿富汗石的特征衍射峰为一组五强峰d=3.682、3.293、2.125、4.825、2.678■,原岩共生矿物包括磷灰石、透辉石、方解石、黄铁矿、方钠石等。In order to analyze the basic gemmological properties and spectroscopy features of afghanite,a series of systematic studies were conducted with the help of standard gemmological methods,X-ray powder diffraction,infrared absorption spectroscopy,laser Raman spectroscopy.The conventional gemmological testing revealed that afghanite was doubly refractive with a refractive index(RI)of 1.522 to 1.529 with a hardness of 5 to 6.These samples displayed varying degrees of bright orange to yellow fluorescence under longwave UV radiation.UV-Vis spectrum showed a wide absorption band centered at approximately 600 nm,which is proprotional to the colour depth of blue,and a weak absorption band centered at approximately 380 nm.Fluorescence and UV-Vis spectra were both influenced by S^3- and S^2-.The FTIR spectra of afghanite in the region between 4000-400 cm^-1 showed that the main peaks at 684,665,614,593,544,433,1005,1119 cm^-1 were accompanied by a shoulder peak at 1166 cm^-1,and two weak peaks at 768,1378 cm^-1 in the fingerprint region,as well as two bands at 3438,1631 cm^-1 in the functional region which corresponded to water molecules.Raman spectra of substrate part of rough samples showed that the characteristic peaks of afghanite were at 260,426,453,542,579,615,989,1083 cm^-1.The testing result of XRD showed that the five strongest peaks at d=3.682,3.293,2.125,4.825,2.678■,which belong to characteristic diffraction peaks of afghanite.In addition,LRM testing confirmed that blue mineral inclusions were lapis lazuli and paragenetic minerals contaning apatite,diopside,calcite,pyrite and sodalite,which were comfirmed by the result of XRD.

关 键 词：阿富汗石 宝石学特征 谱学特征 共生矿物 

分 类 号：TS93[轻工技术与工程] P575.4[天文地球—矿物学]