摘要:
“绿龙晶”(俗称)为一种产自俄罗斯的绿泥石玉,目前普遍认为其矿物组成为斜绿泥石。本次研究用“绿龙晶”样品具有独特的深绿色至灰绿色,呈鳞片状至叶片状结构,密度为2.61~2.62 g/cm3,折射率约为1.57,摩氏硬度约为2.5,其主要矿物组成为绿泥石的亚种叶绿泥石。通过在显微镜下薄片观察发现,叶绿泥石具有靛蓝色、锈褐色和紫色异常干涉色,近平行消光。电子探针结果表明,该“绿龙晶”样品的主要化学成分为SiO2和MgO,其次为Al2O3和FeOT;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。在其X射线衍射图谱中出现了叶绿泥石的14.532 0,7.215 6,4.789 7,3.597 2处的特征衍射峰;其红外光谱中,高频区3 637,3 465 cm-1处的吸收谱带、中频区1 000 cm-1左右分裂的1 048,1 001,967 cm-1吸收峰和低频区444 cm-1处的强吸收谱带显示了叶绿泥石的红外光谱特征。
Abstract:
Lvlongjing is a kind of chlorite jade from Russia,and its mineral component is widely regarded as clinochlore——a subspecies of chlorite.The "Lvlongjing" samples for the study have the unique dark green to celadon colour,lepidoblastic and foliaceous textures,density of 2.61~2.62 g/cm3,refractive index of about 1.57 and Mohs' hardness of about 2.5.The mineral component of the "Lvlongjing" sample is mainly composed of penninite——a subspecies of chlorite.The results of slice observation by microscope show that the penninite has thumb blue,brown and violet anomalous interference colour,parallel or proximal parallel extinction.The EMPA results indicate that the main chemical compositions of the "Lvlongjing" sampe are SiO2 and MgO,followed by Al2O3 and FeOT,and the chemical formula is calculated and projected to be in the area of penninite according to Fe2+/R2+ and atomicity of Si.The XRD result shows that there exist the characteristic diffraction peaks of penninite.The IR absorption peaks of "Lvlongjing" appear at 3 637,3 465,1 048,1 001,967 cm-1 and 444 cm-1 that accord with the IR characteristics of penninite.
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