河南绿色密玉的宝石学特征和颜色成因  

Gemological characteristies and color genesis of green Miyu jade from Henan, China

作　　者：李汶娟 余晓艳[1] 白峰[1] LI Wen-juan;YU Xiao-yan;BAI Feng(School of Gemology,China University of Geosciences(Beijing),Beijing 100083,China)

机构地区：[1]中国地质大学(北京)珠宝学院,北京100083

出　　处：《岩石矿物学杂志》2024年第3期697-708,共12页Acta Petrologica et Mineralogica

摘　　要：河南密玉是我国重要的玉石品种,属于显晶质石英岩。前人对于河南省新密市的密玉玉石矿床进行了系统的地质学研究,但其宝石学特征和颜色成因仍存在争议。文章综合了前人的研究成果,对河南密玉中的绿色系列样品进行了常规宝石学测试、红外光谱测试、紫外-可见光光谱测试、拉曼测试以及电子探针测试研究。结果表明,密玉为结晶度较好的石英岩,主要矿物成分为α-石英,次要矿物有白云母、赤铁矿、石墨、金红石、电气石等;具有花岗变晶结构和显微细粒变晶结构;紫外-可见光光谱中可见明显的Cr^(3+)特征吸收峰;密玉的绿色与含铬白云母有关,而含铬白云母的绿色则是由于其所含的微量元素Cr、V、Ni等致色元素引起的,绿色越深,Cr、Ni、V含量越高;随着Fe^(3+)含量增加,样品的黄色调越明显。Henan Miyu jade is an important variety of jade in China, which belongs to the phanerocrystalline quartzite. A systematic geological study of the Miyu jade deposit in Xinmi City, Henan Province, has been carried out, but its gemmological characteristics and color genesis remain controversial. This paper synthesizes the research results of the previous researchers, and obtains the gemological characteristics, spectroscopic research characteristics and chemical composition characteristics of the green series of Henan Miyu jade samples by routine gemological testing, FTIR spectroscopy, UV-VIs spectroscopy, Raman testing and electron microprobe testing. The results show that Miyu jade is a quartzite with good crystallinity. The main mineral component is α-quartz, and minor minerals include muscovite, hematite, carbonaceous minerals, rutile, tourmaline, etc. It has a granular metamorphic structure and a microscopic fine-grained metamorphic structure. Significant characteristic absorption peaks of Cr^(3+) were seen in the UV-visible spectrum. The green color of Miyu jade is related to chromium-containing white mica, and the green color of chromium-containing white mica is caused by the trace elements it contains, such as Cr, V, Ni and other color-causing elements. The darker the green color, the higher the content of Cr, Ni and V. With the increase of Fe^(3+) content, the yellow tone of the sample is more obvious.

关 键 词：绿色密玉 石英质玉 宝石学特征 颜色成因 河南 

分 类 号：P578.494[天文地球—矿物学]