【作者】 于方； 范桂珍； 朱子玉； 何志红；

【Author】 YU Fang;FAN Gui-zhen;ZHU Zi-yu;HE Zhi-hong;

【机构】 北京大学宝石鉴定中心；

【摘要】 "绿龙晶",为产出于俄罗斯的一种玉石,目前普遍认为其矿物成分为绿泥石的亚种斜绿泥石。"绿龙晶"具有独特的深绿至灰绿色和鳞片状至叶片状结构,密度为2.61².62 g/cm^-3,折射率为1.57左右,摩氏硬度为2.5左右。矿物学特征的研究表明,绿龙晶的主要矿物成分为绿泥石的亚种叶绿泥石。显微镜下薄片观察,叶绿泥石矿物具有靛蓝色、锈褐色和紫色的异常干涉色,近平行消光。电子探针的结果表明,绿龙晶的主要化学成分为SiO₂和MgO,其次为Al₂O₃和FeO;计算其晶体化学式并根据Fe²⁺/R²⁺和Si的原子数量进行投影,恰好落于叶绿泥石的区域范围。X射线衍射图谱中,出现了叶绿泥石的14.5320A,7.2156A,4.7897A,3.5972A的特征衍射峰。红外光谱图中,高频区3637cm^-1、3465 cm^-1吸收谱带、中频区1000cm^-1左右分裂的1048cm^-1、1001cm^-1、967cm^-1三个吸收峰和低频区444cm^-1的强吸收谱带,显示了叶绿泥石的红外光谱特征。更多还原

【Abstract】 Serapbinite is a kind of jade from Russia,which mineral composition is wildly considered as clinochlore（a subspecies of chlorite）.Seraphinite has unique dark green to celadon color,lepidoblastic and foliaceous texture,density of 2.61 2.62,a refraction index of 1.57,and mohs hardness of about 2.5.Study on mineral composition of seraphinite shows that it is composed of penninite-a subspecies of chlorite.Thin section observation by polarizing microscope shows that the penninite of seraphinite has thumb blue,brown and violet anomalous interference color,parallel or proximal parallel extinction.The EMPA results indicate that the main chemical composition of seraphinite is SiO₂ and MgO followed by Al₂O₃ and FeO,the chemical formula is calculated and projected to be in the area of penninite according to atomicity of Fe²⁺/R²⁺ and Si.XRD shows that there coexist the characteristic diffraction peaks of penninite.The IR absorption apectra show 3637cm^-1,3465 cm^-1,1048cm^-1,1001cm^-1,967cm^-1 and 444 cm^-1 bands that are the IR characteristics of penninite.更多还原