【作者】 李曦；

【导师】 何明跃；

【作者基本信息】 中国地质大学(北京) ， 宝石学， 2012， 硕士

【摘要】 紫色翡翠主要分为三个系列：粉紫色系列翡翠、正紫色系列翡翠、蓝紫色系列翡翠。本文主要从紫色翡翠的物理性质、结构构造、矿物组成及化学成分、矿物晶体结构、呈色机理等方面对其进行系统的宝石学研究。天然紫色翡翠，常成似晶簇构造、角砾构造。其紫色斑晶，具有环带状结构，形成于静态重结晶作用，动力变质作用不明显。在形成的时间上，紫色硬玉属于较早世代，结晶时间与同一世代的白色硬玉一致或者略晚。通过红外光谱、粉晶衍射等实验，发现紫色系列翡翠的矿物组成以硬玉为主，而其他矿物由于含量少，未能在光谱中体现，说明硬玉中的类质同象替代造成了其紫色的产生。通过电子探针实验、LA-ICP-MS实验，证明正紫色翡翠中含有较高含量的Mn，Fe；粉紫色翡翠中具有一定含量的Mn，而Fe元素远远低于正紫色与蓝紫色系列；蓝紫色翡翠中含有远高于正紫色与粉紫色的Fe、Ti，也具有一定量的Mn，且V、Co、Ba在蓝紫色翡翠中有一定的增加，可能对饱和度等方面一定的影响。通过电子探针测试，还在灰紫色色斑中发现了钡长石矿物。对稀土元素的研究中，可知稀土总量偏低，其中轻稀土元素的含量高于重稀土元素的含量，中稀土亏损。除蓝紫色系列翡翠Eu异常为正异常外，其他紫色系列翡翠为负异常。除正紫色翡翠Ce异常为正异常外，其他紫色系列翡翠为负异常。根据加热前后紫外光谱谱峰的对比，并结合微量元素的实验结果，可知正紫色翡翠以580nm为吸收特征，在加热后正紫色翡翠变为黄色，谱线发生巨大改变，可见其主要由于Mn³⁺致色，Fe²⁺对其颜色具有一定的影响；粉紫色翡翠388nm和437nm吸收随着粉色调的增加而逐步消失，即Fe元素越少则粉色调越深，并且随着Fe的减少，580nm逐渐靠近570nm附近处，则其致色机理与正紫色系列翡翠相同；蓝紫色翡翠以540nm、620nm、760nm的吸收有异于粉紫色至正紫色系列的翡翠。加热后，其光谱388nm吸收减小，近于消失，437nm、540nm、620nm、760nm的吸收也得到了减弱，但整体谱线趋势影响不大，结合微量元素特征，则其为Ti⁴+、Fe²+共同致色，Mn³+可能也参与了致色。更多还原

【Abstract】 Lavender feicui is divided into three series: pink purple feicui series, purple feicui series, and blue purple feicui series.Lavender feicui in this paper focused onphysical properties,texture and structure,mineralogical and chemical compositions ofminerals as well as crystalline structure.Commonly Natural lavender feicui is drusy structures and brecciated texture. Itspurple phenocrysts has zonal structure, formed from static recrystallization, dynamicmetamorphism is not obvious. Some of samples have green parts, the texture of whichis fibrous and radial. It illustrates that purple jadeite formed in earlier period andcrystallized as early as contemporaneous white jadeite, or possibly a little later.Through infrared spectroscopy,powder diffraction experiments, it shows that themajor mineral composition of lavender feicui is jadeite, and other mineral contentless cannot be reflected by spectrum owing to low content. Hence the isomorphism injadeite causes the color of lavender feicui.Through electron prove microanalysis （EPMA） and LA-ICP-MS,the results showthat purple feicui has a high content of Mn,Fe. Blue-purple feicui contains moreFe,Ti than pink-purple and purple feicui. And V,Co,Ba element in the blue-violet feicuimay impact on value and saturation. Pink-purple feicui has a certain content of Mn butless Fe than purple and blue-purple feicui.And find celsian in the phenocrysts.Thelavender feicui are characterized by MREE-depleted,both of HREE and LREE-enrichedpattern,and the content of LREE is more than HREE.Except blue feicui with asignificantly positive Eu,other series of lavender feicui with nagtive Eu.Except purplefeicui with a significantly positive Ce,other series of lavender feicui are nagtive in Ce.Through UV spectrum of heating contrast experiments, combined with traceelements test, the purple feicui absorption spectral feature is in580nm，thespectrogram shows that purple feicui is mainly because Mn³⁺,Fe²⁺ also has certainimpact color of purple. Pink purple feicui contains certain amount of of Mn³⁺, butvery little Fe²⁺.Blue purple feicui, Ti4+and Fe²⁺ induced color are reason forcolor,and Mn³⁺ may also have a impact of color.更多还原