贵州罗甸和田玉及其“花斑状”包裹体特征  

Characteristic of Hetian Yu from Luodian,Guizhou Province,China and Its"Piebald"Inclusions

作　　者：闫冰 李慧纹 尹作为[1,2] YAN Bing;LI Huiwen;YIN Zuowei(Gemmological Institute,China University of Geosciences,Wuhan 430074,China;Hubei Gems and Jewelry Engineering Technology Research Center,Wuhan 430074,China)

机构地区：[1]中国地质大学(武汉)珠宝学院,湖北武汉430074 [2]湖北省珠宝工程技术研究中心,湖北武汉430074

出　　处：《宝石和宝石学杂志(中英文)》2024年第6期70-78,共9页Journal of Gems & Gemmology

基　　金：中国地质大学(武汉)珠宝学院开放基金(CIGTXM-04-S202119)。

摘　　要：自发现贵州省罗甸县和田玉玉矿后,关于其宝石学特征等方面的研究旋即开展,至今已渐成体系。但诸如其表面及近表面普遍存在并具有产地指示意义的“花斑状”包裹体的研究却较为匮乏。于此,本文通过常规宝石学测试、显微观察、红外吸收光谱、激光拉曼光谱和电子探针等手段,获取贵州省罗甸县和田玉的详细谱学特征、包裹体特征和成分特征等,以期丰富不同产地和田玉的理论研究。结果表明,罗甸和田玉样品颜色主要包括灰白色、青白色和青色,常见白色条带及黑色、棕色“花斑状”包裹体,抛光后样品呈弱油脂光泽,具明显瓷器感,微透明,相对密度为2.81~2.90。罗甸和田玉平均化学式为(Ca_(1.75)^(2+)Na_(0.05)^(+)K_(0.02)^(+))_(1.82)(Mg_(4.96)^(2+)Al_(0.03)^(3+)Fe_(0.02)^(3+))_(5.01)[Si_(8.07)^(4+)O_(22)](OH)_(2)。红外光谱和拉曼光谱均表证了主要矿物为透闪石,部分样品在红外光谱中出现855 cm^(-1)处吸收,为副矿物透辉石所致;拉曼光谱及能谱面扫描表明,“花斑状”包裹体富集Mn元素,其在640 cm^(-1)附近出现的宽带散射,指示其为锰氧化物,与[MnO6]八面体的Mn-O对称伸缩振动有关,同时在154、280、710 cm^(-1)和1085 cm^(-1)处出现散射峰,为副矿物方解石所致。Since the discovery of Hetian Yu deposits in Luodian,Guizhou Province,China,a large number of gemmological studies have been carried out and gradually formed a system.However,there are few studies on the commonly distributed"piebald"inclusions that have significant origin characteristics on or near the surface of the Hetian Yu.To obtain the spectral characteristics,inclusion features and chemical compositions of Hetian Yu from Luodian,conventional gemmological tests,microscopic photography,infrared spectroscopy,Raman spectroscopy and electron probe had been implemented.The results showed that the colour of Hetian Yu samples from Luodian is mainly gray white,bluish white and cyan.Besides,there are possible white bands and black to brown"piebald"inclusions on Hetian Yu.After polishing,the samples show a weak grease luster,a clear porcelain sense and slightly transparent.The specific gravity ranges from 2.81 to 2.90.The average chemical formula of Hetian Yu from Luodian is(Ca_(1.75)^(2+)Na_(0.05)^(+)K_(0.02)^(+))_(1.82)(Mg_(4.96)^(2+)Al_(0.03)^(3+)Fe_(0.02)^(3+))_(5.01)[Si_(8.07)^(4+)O_(22)](OH)_(2).Both infrared spectra and Raman spectra show characteristic spectra of tremolite.Some samples show absorbing at 855 cm^(-1) in the infrared spectrum due to the accessory mineral of diopside.EDS mapping images and Raman spectrum,indicate that the"piebald"inclusions are enriched with Mn elements,and their broadband scattering around 640 cm^(-1) indicates that they are manganese oxides,which is related to the Mn-O symmetric stretching vibration of the[MnO6]octahedron.Meanwhile there can be accompanied by scattering peaks at 154,280,710 cm^(-1) and 1085 cm^(-1) caused by calcite accessory mineral.

关 键 词：和田玉 包裹体特征 谱学特征 罗甸玉 贵州省罗甸县 

分 类 号：TS93[轻工技术与工程]