巴基斯坦氟磷锰矿的宝石学及谱学特征  

Gemmological and Spectral Characteristics of Triplite from Pakistan

作　　者：曲直 李鹏 刘平 招博文[2] QU Zhi;LI Peng;LIU Ping;ZHAO Bowen(Qingdao Institute of Measurement Techology,Qingdao 266071,China;Shanghai Institute of Measurement and Testing Technology,Shanghai 201203,China)

机构地区：[1]青岛市计量技术研究院,山东青岛266071 [2]上海市计量测试技术研究院,上海201203

出　　处：《宝石和宝石学杂志（中英文）》2022年第5期125-133,共9页Journal of Gems & Gemmology

摘　　要：氟磷锰矿是富磷花岗岩中的一种原生矿物,宝石级氟磷锰矿仅在巴基斯坦北部希格尔河谷地区有产出。以该地区产出的宝石级氟磷锰矿为研究对象,通过常规宝石学测试、红外光谱、紫外-可见光谱、激光拉曼光谱以及电子探针等测试仪器对其进行测试与研究。结果表明,宝石级氟磷锰矿样品呈橙黄色-橙红色,折射率为1.662~1.690,双折率约为0.026,多色性不明显;在长、短波紫外灯下均为惰性,放大可见刻面棱重影、矿物及流体包裹体,密度为3.6~3.8 g/cm^(2),摩氏硬度为5~6。氟磷锰矿样品具有特征的红外光谱以及拉曼光谱:红外光谱主要特征吸收峰位于1134、1073、1042、969、628、598、580、446 cm^(-1),可作为氟磷铁锰矿归属于磷酸盐的鉴定依据;拉曼光谱中特征峰428、455、610、980、1037、1071、1129 cm^(-1)和3451~3471 cm^(-1)为氟磷锰矿诊断性依据。电子探针详细测定的样品成分,样品的化学计算式与(Mn,Fe)_(2)(PO_(4))F化学式吻合。紫外-可见吸收光谱并结合电子探针分析结果,可以判定氟磷锰矿的颜色主要由Mn^(2+)和Fe^(2+)离子所致,红色调随Fe^(2+)含量的增加而加深。Triplite is a primary mineral in phosphorus-rich granite.It is one of the rarest gems that has been discovered recently in Pakistan.5 pieces of triplite samples from Pakistan were collected and studied by conventional gemmological tests and advanced instrumentation including energy dispersive X-ray fluorescence spectrometer,EPMA,UV-Vis,Fourier transform infrared spectrometer,and Raman spectrometer.The results showed the colour of the triplite is from orange yellow to orange,and its polished facet shows glassy lustre.It showedinert under LW and SW ultra-violet lamp.The refractive index is 1.662-1.690,and birefringence is 0.026.The density is 3.6-3.8 g/cm^(3),and its Mohs hardness is 5-6.Triplite has characteristic Raman and FTIR spectra.FTIR results indicate that the most characteristic part is O-P-O stretch vibration between 900-1200 cm^(-1),absorption peaks around 400-700 cm^(-1) belong to bending vibration and stretch vibration.And its Raman spectrum shows peaks of 428、455、610、980、1037、1071、1129 cm^(-1) and 3451-3471 cm^(-1) are triplite’s identification bases.EPMA and XRF result show Fe,Mn,P and other elements from tested samples which meets triplite’s chemical formula(Mn,Fe)_(2)(PO_(4))F.Through the analysis of UV-Vis fluorescence spectra,it can be concluded that the colour of triplite may be related to its Mn^(2+) and Fe^(2+) ions element.The colour of the sample deepens with the increase of Fe^(2+) ions content.

关 键 词：氟磷锰矿 磷酸盐 电子探针 颜色成因 巴基斯坦 

分 类 号：TS93[轻工技术与工程]