摘要
品质和产地是影响祖母绿价格的重要因素,而不同产地祖母绿的宝石学特征是其产地溯源的重要依据之一。本文以阿富汗潘杰希尔(Panjsher)矿区祖母绿样品为研究对象,运用了光学显微镜、红外光谱仪、显微紫外-可见-近红外光谱仪、拉曼光谱仪等大型仪器对样品的宝石矿物学特征、内部包裹体特征、化学成分和颜色成因等进行了测试分析。结果显示,该地区祖母绿样品的颜色为浅绿色-深绿色,常见晶形为六方短柱状或板状晶体,外部可见黑色、褐色伴生矿物,查尔斯滤色镜下除个别样品外均局部变红。祖母绿样品的主要包裹体多为长针状、梭状或长管状的含岩盐-钾盐的多相流体包裹体以及固相矿物包裹体。拉曼光谱对包裹体测试后发现其多相包裹体中液相成分多为H 2 O,固体相成分多为方解石和赤铁矿,矿物包裹体主要成分多为赤铁矿、方解石、无定形碳、石英、碳质和磷灰石等;LA-ICP-MS的化学成分结果显示,该产地祖母绿样品的主要化学成分为BeO、Al 2 O 3、SiO 2,微量元素主要有Ca、Mg、Ti、Li、Na、K、Rb、Cs、Cr、V;红外光谱的测试结果显示该产地祖母绿样品含有Ⅰ型水和Ⅱ型水,且Ⅱ型水的红外吸收峰强度大于Ⅰ型水,以Ⅱ型水为主,与LA-ICP-MS测试结果中碱金属的含量高相一致;紫外-可见光谱结果显示,Cr 3+和V 3+为阿富汗潘杰希尔矿区祖母绿样品的主要致色离子。综上,阿富汗潘杰希尔矿区祖母绿的宝石学特征、谱学特征和化学成分可为其产地溯源提供一定的参考依据。
Quality and origin are important factors affecting the price of emerald.Emeralds from different origins have their own gemmological characteristics,which are important basis to trace their hometown.This study takes the emerald samples from the Panjshir mining area in Afghanistan as the research objects,and uses large-scale instruments such as optical microscopy,infrared spectroscopy,micro ultraviolet visible near-infrared spectroscopy,Raman spectroscopy,etc.to conduct study on their gemmological characteristics,internal inclusion characteristics,chemical compositions,and colour genesis.The colour of emerald samples from Afghanistan is light green to dark green,and the common crystal form is hexagonal short columnar or tabular crystal.Black and brown associated minerals can be seen outside.Under the Charles filter,all except a few samples showed localized redness.The main inclusions of emerald samples from Afghanistan are long needle-like,shuttle-like or long tube-like multiphase fluid inclusions containing rock salt and potassium salt and solid mineral inclusions.Raman spectrum tests on inclusions found that the liquid component of multiphase inclusions in emerald samples from Afghanistan is mostly H 2 O,and the solid component is mostly calcite and hematite.In addition,mineral inclusions contained in emerald are mainly composed of hematite,calcite,amorphous carbon,quartz,carbonaceous,apatite,etc.LA-ICP-MS was used to test the chemical compositions of the emerald samples from Afghanistan,the result indicated that the main chemical compositions of the emerald samples are BeO,Al 2 O 3,SiO 2,and trace elements including Ca,Mg,Ti,Li,Na,K,Rb,Cs,Cr,V.Through infrared spectroscopy test,it is known that emerald from Afghanistans contain typeⅠand typeⅡwater,and the infrared absorption peak intensity of typeⅡwater is greater than that of typeⅠwater,indicating that emerald samples from Afghanistans are mainly composed of typeⅡwater.The alkali metal content in general beryl(and emerald)is positively correlated with
作者
董信
陈涛
周征宇
DONG Xin;CHEN Tao;ZHOU Zhengyu(Gemmological Institute,China University of Geosciences,Wuhan 430074,China;Hubei Gems and Jewelry Engineering Technology Research Center,Wuhan 430074,China;School of Ocean and Earth Science,Tongji University,Shanghai 200082,China)
关键词
祖母绿
谱学特征
包裹体
阿富汗潘杰希尔
emerald
spectral characteristic
inclusion
Panjsher,Afghanistan
