一种云母石英质玉“草莓晶”的宝石学及振动光谱特征  

Gemmological and Vibrational Spectrum Characteristics of Micaceous Quartzose Jade“Strawberry Crystal”

作　　者：金晓婷 李国贵 廖冰冰 李雪明[1] 龙楚[1] JIN Xiaoting;LI Guogui;LIAO Bingbing;LI Xueming;LONG Chu(Guangdong Provincial Gem & Precious Metal Testing Center, Guangzhou 510080, China;Chengdu Institute of Product Quality Inspection Co.,Ltd., Chengdu 610100, China;Guangdong Research Center for Geoanalysis, Guangzhou 510080, China)

机构地区：[1]广东省珠宝玉石及贵金属检测中心,广东广州510080 [2]成都产品质量检验研究院有限责任公司,四川成都610100 [3]广东省地质实验测试中心,广东广州510080

出　　处：《宝石和宝石学杂志》2021年第3期19-28,共10页Journal of Gems & Gemmology

基　　金：国家自然科学基金项目(49772096)。

摘　　要：云母石英质玉为新近出现的一种玉石,其商贸名称为“草莓晶”。针对该玉石检测与研究过程中出现的问题,采用显微激光拉曼光谱仪、傅里叶变换显微红外光谱仪、X射线能谱仪等分析测试方法,重点就云母石英质玉的宝石矿物学、振动光谱及其致色机理等特征进行了研究。结果表明,云母石英质玉主要由显晶质石英集合体组成,次要(致色)矿物为含锰铁白云母,具典型的鳞片粒状结构,其紫红色调的形成与其次要矿物含锰铁白云母中Mn^(2+)的外层d电子^(6)A_(1)→^(4)T_(1)(^(4)G)跃迁导致的554 nm吸收峰,^(6)A_(1)→^(4)T_(2)(4G)跃迁导致的445 nm吸收峰及Fe^(2+)的自旋禁戒跃迁产生的516 nm吸收峰密切相关。含锰铁白云母中由Al-(Fe,Mn)-OH伸缩振动导致的红外吸收谱带位于3616 cm^(-1)处,由硅氧骨干振动导致的一组拉曼峰分别位于1071、746、697、628、408 cm^(-1)处,由晶格振动和阳离子交换导致的拉曼峰分别位于261 cm^(-1)和191 cm^(-1)处,据此与相似的云母类矿物相区分。Micaceous quartzose jade is a new kind of jade recently appeared on the market,and its trade name is“strawberry crystal”.In view of the problems faced in the tests and researches of the jade,microscopic laser Raman spectrometer,Fourier transform microscopic infrared spectrometer and X-ray energy spectrometer were used to study the characteristics of mineralogy,vibration spectrum and colouring mechanism of the jade.The results showed that the micaceous quartzose jade is mainly composed of crystalline quartz and the secondary(colouring)mineral is manganese-iron bearing muscovite with typical scaly and granular structure.The formation of the purplish red hue of this kind of mica is closely related to the 554 nm absorption peak caused by ^(6)A_(1)→^(4)T_(1)(4G)transition.The 445 nm absorption peak is caused by the ^(6)A_(1)→^(4)T_(2)(4G)transition of delectron of the outer layer of the Mn^(2+),and the 516 nm absorption peak is caused by the spin forbidden transition of Fe^(2+).The infrared absorption band of manganese-iron bearing muscovite caused by stretching vibration of Al-(Fe,Mn)-OH is located at 3616 cm^(-1),and a group of Raman peaks caused by silica backbone vibration are located at 1071,746,697,628 cm^(-1) and 408 cm^(-1),respectively.The Raman peaks caused by lattice vibration and cation exchange are located at 261 cm^(-1) and 191 cm^(-1) respectively,which are distinguished from similar mica group minerals.

关 键 词：云母石英质玉 含锰铁白云母 红外光谱 拉曼光谱 

分 类 号：TS93[轻工技术与工程]