一种多颜色纹层大理岩玉的宝石矿物学特征  

Gemmological and Mineralogical Characteristics of Multicolour Laminated Marble Jade

作　　者：余炼钢 刘衔宇 YU Liangang;LIU Xianyu(Dehong Teachers’College,Dehong 678400,China;School of Jewelry,Shanghai Jian Qiao University,Shanghai 201306,China)

机构地区：[1]德宏师范高等专科学校,云南德宏678400 [2]上海建桥学院珠宝学院,上海201306

出　　处：《宝石和宝石学杂志（中英文）》2023年第5期106-112,共7页Journal of Gems & Gemmology

基　　金：2021年云南省教育厅科学研究基金项目(2021J1166)。

摘　　要：近年来云南珠宝市场兴起了一类造型奇特、富有情趣的观赏石,俗称“猪肉石”,因其颜色及纹理特征特殊而得名。利用常规宝石学方法、显微岩相学及多种现代测试技术对该类观赏石样品的矿物组成及谱学特征进行测试分析。结果显示,该类观赏石样品呈油脂-蜡状光泽、半透明-微透明,由白色、黄色、褐色、红色等多色纹层构成,整体结构定向特征明显;显微岩相学及X射线粉末衍射分析表明其主要矿物组成为碳酸盐,包括方解石和极少量的菱镁矿,约占90%以上,其次为含氧化铁泥灰质,约占5%~10%,以及微量的泥质残留物;偏光显微镜下可见明显的方解石变质重结晶及聚片双晶特征;红外光谱在712、875、1420 cm^(-1)处具有特征吸收峰,分别归属[CO_(3)]^(2-)的面内弯曲振动ν4、面外弯曲振动ν2、以及反对称伸缩振动ν3,其中ν4指示主要成分为方解石;拉曼光谱在1086、713、281 cm^(-1)处的拉曼峰由[CO_(3)]^(2-)的面外弯曲振动、面内弯曲振动以及晶格振动所致;化学成分分析显示样品除有CaCO_(3)外,还含有Al、Fe、Mn、Ti等多种微量元素,并结合其紫外-可见光光谱特征可知Fe和Mn元素是其产生红色、黄色、褐色的主要原因,Fe和Mn的含量越高颜色越深。综上,该类观赏石样品是含少量铁泥灰质的钙镁碳酸盐类矿物,依据国家标准《珠宝玉石名称》GB/T 16552-2017,应定名为大理岩玉或碳酸盐质玉。A new kind of ornamental stone in the domestic jewelry market is becoming popular in recent years,because of its similar appearance to the pork.In this paper,the mineral components and spectral characteristics of the ornamental stone samples were analyzed by conventional gemmological tests,micro-petrography and a variety of modern testing techniques.The results show that the ornamental stone is composed of white,yellow,brown,red and various other coloured bands,it has oil waxy luster,translucent to slightly transparent.The overall structure has a remarkable orientation.Micro-petrography and X-ray powder diffraction analysis show that the main mineral component is carbonate,accounting for more than 90%,including calcite and a small amount of magnesite.The secondary minerals are iron bearing marl such as iron oxide,accounting for about 5%-10%.In addition,there are argillaceous residues formed by recrystallization of very small amounts of calcite,with medium coarse-grained crystalloblastic structure as a whole.Under polarizing microscope,the characteristics of calcite metamorphism and recrystallization are obvious and the characteristics of lamellar bicrystal can be seen.The infrared spectra show characteristic infrared absorption peaks at 712,875,1420 cm^(-1),which are respectively attributed to the in-plane bending vibrationν4,out-of-plane bending vibrationν2,anti-symmetric stretching vibrationν3 of[CO_(3)]^(2-),and the vibration modeν4 indicates that the main component is calcite.Raman spectra have characteristic Raman shift peaks at 1086,713 cm^(-1)and 281 cm^(-1),which are attributed to the out-of-plane bending vibration,in-plane bending vibration and lattice vibration of[CO_(3)]^(2-).Both infrared spectra and Raman spectra indicate the vibration mode of carbonate groups.The chemical composition analysis show that in addition to CaCO_(3),the ornamental stone samples also contain a variety of trace metal elements such as Al,Fe,Mn and Ti.Fe and Mn is the colour origin of the yellow,brown and red bands.The hig

关 键 词：大理岩玉 矿物组成 光谱特征 成因机理 

分 类 号：P575[天文地球—矿物学] TS93[天文地球—地质学]