青海野牛沟软玉的宝石矿物学及谱学特征  

Mineralogical and Spectroscopy Characteristics of the Nephrite in Yeniugou,Qinghai

作　　者：陶隆凤 郝楠楠 金翠玲 史淼 韩秀丽 TAO Long-feng;HAO Nan-nan;JIN Cui-ling;SHI Miao;HAN Xiu-li(College of Mining Engineering,North China University of Science and Technology,Tangshan 063210,China;School of Gemmology and Materials Science,Hebei GEO University,Shijiazhuang 050031,China;Hebei Key Laboratory of Green Development of Rock Mineral Materials,Shijiazhuang 050031,China;Shandong Xiajin Economic Development Zone Administration,Dezhou 253000,China)

机构地区：[1]华北理工大学矿业工程学院,河北唐山063210 [2]河北地质大学宝石与材料学院,河北石家庄050031 [3]河北省岩石矿物材料绿色开发重点实验室,河北石家庄050031 [4]山东夏津经济开发区管理委员会,山东德州253000

出　　处：《光谱学与光谱分析》2024年第11期3165-3171,共7页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(42002156);河北地质大学国家预研项目(KY2024QN07)资助。

摘　　要：青海省格尔木地区是我国重要的软玉产区,其中野牛沟位于东昆仑山系中段,是软玉的主要产出矿点之一。对野牛沟黄绿色软玉样品进行了常规宝石学、红外光谱(FTIR)、拉曼光谱、电子探针(EPMA)等测试及薄片观察,并分析了其矿物学和谱学特征。结果表明,该区软玉的折射率为1.61,相对密度约2.97~2.99,摩氏硬度6~6.5,玻璃-油脂光泽,结晶度较好。样品基质的组成矿物为透闪石,次要矿物为透辉石、绿帘石、榍石、磷灰石等,其中基质的氧化物含量为w(SiO_(2))=58.92~59.40%,平均值59.19%,w(MgO)=24.70%~25.56%,平均值24.98%,w(CaO)=13.15%~13.43%,平均值13.29%,粒径约为0.01~1.00 mm,具有典型的毛毡状交织结构和显微纤维变晶结构,部分可见显微放射状变晶结构——帚状结构,各项矿物学特征均符合软玉国家鉴定标准。该区软玉样品的红外光谱和拉曼光谱均与透闪石的谱峰基本一致,其中样品在468 cm^(-1)处的红外吸收光谱强度高于509 cm^(-1)处,部分红外光谱和拉曼光谱峰位发生了红移或蓝移现象,结合化学成分分析,认为该区软玉中的透闪石为钙质角闪石,谱峰的偏移与样品中所含Fe、Mn元素或晶体结构有关。结合矿物学特征、电子探针测试及野外实地考察,认为青海野牛沟软玉矿体是在镁质大理岩、基性辉绿岩及后期中酸性岩浆热液的共同作用下成矿,同时剪切作用也对软玉矿的品质起着重要作用。该研究,基本确定了青海野牛沟矿区软玉的矿物学和谱学特征,也对其成矿环境进行了探讨,为该区的找矿及深部成矿预测提供依据。The nephrite deposits in China are mainly distributed in Qinghai provinces,among which Yeniugou County is one of the most important nephrite deposits.In this paper,the yellow-green nephrite samples of Yeniugou were tested by conventional gemmology,infrared spectroscopy(FTIR),Raman spectroscopy,electron probe microanalysis(EPMA),and thin section observation,and their mineralogical and spectral characteristics were analyzed.The results show that the refractive index of nephrite in this area is 1.61,the relative density is about 2.97~2.99,the Mohs hardness is 6~6.5,its luster is glass-oil,and the crystallinity is good.The matrix mineral of the sample was tremolite,and the minor minerals were diopside,epidote,sphene,apatite,etc.The contents of oxides in the matrix were w(SiO_(2))=58.92%~59.40%,with an average value of 59.19%,w(MgO)=24.70%~25.56%,with an average value of 24.98%,w(CaO)=13.15%~13.43%,with an average value of 13.29%.The particle size of the mineral is about 0.01~1.00 mm.The mineral has a typical felt-like interwoven texture and microscopic dermatoplastic texture,and some micro radial dermatoplastic texture-broom texture can be seen.All mineralogical characteristics are in line with the national identification standard of nephrite.The infrared and Raman spectra of nephrite samples in this area are consistent with the spectral peaks of tremolite.However,the infrared spectral intensity of the sample at 468 cm^(-1)is higher than that at 509 cm^(-1),and certain peaks in both the infrared and Raman spectra display red or blue shifts.Combined with the chemical composition analysis,it is considered that the tremolite in nephrite is calcareous hornblende,and the shift of spectral peak is related to the Fe,Mn elements or crystal structure.Based on mineralogical characteristics,electron probe test,and field investigation,it is concluded that the nephrite ore body in Yeniugou was formed under the joint action of magnesian marble,basic diabase,and late intermediate-acid magmatic hydrothermalism.Meanwhile,shearing pla

关 键 词：软玉 野牛沟 透闪石 矿物组成 谱学特征 

分 类 号：O461.3[理学—电子物理学]