硬地昌化鸡血石与其相似品种的矿物学特征研究

Study on Mineralogical Characteristic of Hard Substrate Chicken-Blood Stone (Changhua) and Its Similar Varieties

  • 摘要: 鸡血石由“血”和“地”组成,其中“血”的主要矿物为辰砂,“地”的主要矿物为地开石、高岭石、叶蜡石和明矾石。针对市场上出现一些真“血”假“地”的鸡血石相似品种,本文通过鸡血石的矿物学特征对鸡血石及其相似品种进行了深入研究。选取硬地昌化鸡血石和其他四个不同产地(西安、贵州、青海、四川)“鸡血石”为研究对象,利用偏光显微镜、X射线粉末衍射、电子探针,获取各产地鸡血石样品的主要矿物组成、矿物组合特征及化学成分等信息,研究硬地昌化鸡血石与相似品种的特征差异。硬地昌化鸡血石样品含有石英、辰砂、伊利石、地开石、一水铝石和黄铁矿。硬地昌化鸡血石中可见部分石英为自形结构,并有明显的硅化现象,石英与辰砂可见共生接触关系。黄铁矿为自形晶,但溶蚀较严重,呈星点状分布;辰砂以团块状和斑点状分布;西安“鸡血石”样品含有石英、辰砂、白云石、辉锑矿、黄铁矿以及重晶石。辉锑矿含量较少,该西安“鸡血石”样品中未见辉锑矿与辰砂的共生接触现象。黄铁矿未见自形晶,溶蚀较严重,星点状围绕辰砂集合体分布。辰砂为粒状集合体、片状,以团块状和网脉状分布;贵州“鸡血石”样品含有石英、辰砂、辉锑矿、黄铁矿。辉锑矿含量较多,与辰砂为共生关系。黄铁矿可见自形晶,含量较其他产地高,呈星点状和细脉状分布。辰砂以浸染状和团块状分布;青海“鸡血石”样品含有石英、辰砂、铁白云石和黄铁矿。其中辰砂具有明显的两期成矿的特征,辰砂以蛛网状和团块状分布。青海“鸡血石”中石英同样具有两期成矿特点;四川“鸡血石”样品含有石英、辰砂和少量白云石,其中石英可见切面为六边形的自形晶。辰砂单晶为粒状,在斜照光下颗粒可见彩色闪光,以团块状和脉状分布。利用X射线粉末衍射测试结果计算了硬地昌化鸡血石与相似品种中辰砂的晶胞参数,结果表明,硬地昌化鸡血石与相似品种中辰砂均满足三方晶系结构特征,且硬地昌化鸡血石中辰砂具有较大的a轴长度和较小的c轴长度;对比辰砂的电子探针实验数据发现,硬地昌化鸡血石中辰砂不含Cu,青海和四川“鸡血石”辰砂中不含Sb。贵州、青海和四川“鸡血石”辰砂中Hg元素可能被Fe、Ni、Cu等元素少量替代;通过能谱仪对样品中不确定矿物进行能谱及元素含量分析发现,在西安“鸡血石”样品中有辰砂与重晶石的伴生。本研究从矿物学角度表征了硬地昌化鸡血石与相似品种的矿物学特征,为硬地昌化鸡血石及相似品种的鉴定提供了基础材料。

     

    Abstract: The chicken-blood stone is composed of "blood" and "substrate", in which the main mineral of "blood" is cinnabar and the main minerals of "substrate" are dickite, kaolinite, pyrophyllite, and alunite.To better identify the mineralogical characteristics between hard substrate chicken-blood stone from Changhua and its similar varieties, samples obtained from the market with real "blood" and fake "substrate" were studied in-depth. In this study, hard substrate Changhua chicken-blood stone and its similar varieties (from Xi'an, Guizhou, Qinghai and Sichuan) were collected. In order to study the mineralogical differences between hard substrate chicken-blood stone and its similar varieties, the main mineral composition, mineral assemblage characteristics, and chemical composition were obtained by polarizing microscope, X-ray powder diffraction (XRD) and electron probe microscope analysis (EPMA).In the studied samples, hard substrate Changhua chicken-blood stone contains cinnabar, quartz, illite, dickite, diaspore and pyrite. The cinnabar is massive and occurs as spotted distribution. The quartz is automorphic and silicification phenomenon is widespread and obvious in the hard substrate Changhua chicken-blood stone. The cinnabar exhibits metasomatic and parageneticcontact with quartz. The pyrite is automorphic, but seriously dissolved, and stellate distributed around cinnabar.The Xi'an "chicken-blood stone" contains quartz, cinnabar, dolomite, stibnite, pyrite and barite. The cinnabar presents granular aggregate and occurs as flake-like shapes showing massive and reticular distribution.The content of stibnite is low and there is no paragenetic contact between stibnite and cinnabar in the sample of Xi'an "chicken-blood stone"; The pyrite does not exhibit automorphic and is seriously dissolved, star-like distributing around cinnabar aggregate.The Guizhou "chicken-blood stone" contains quartz, cinnabar, stibnite and pyrite. The cinnabar presents disseminated and massive distribution.The pyrite shows automorphicmorphology with star and veinlets distribution characteristics, and the content of which is higher than that of compared samples.The Qinghai "chicken-blood stone" contains quartz, cinnabar, iron dolomite, and pyrite. The cinnabar in Qinghai "chicken-blood stone" occurs as obvious two-stage mineralization and presents cobweb and massive distribution characteristics. The quartz in the Qinghai "chicken-blood stone" shows obvious two-stage mineralization as well.The Sichuan"chicken-blood stone" contains quartz, cinnabar and a small amount of dolomite. The quartz exhibits automorphic with hexagonal morphology. The cinnabar shows scaly, massive, and veiny distribution patterns and its flash can be observed under oblique light.In addition, the cell parameters of the hard substrate Changhua chicken-blood stone and its similar varieties were calculated the data from XRD. The results show that the cinnabar of hard substrate Changhua chicken-blood stone and its similar varieties meet the structural characteristics of tripartite system, and the cinnabar in the hard substrate Changhua chicken-blood stone has parameters of a larger a-axis length and a shorter c-axis length, comparing to the cinnabar in the other samples.Through the comparative analysis of cinnabar by EPMA, it is found that there is no Cu in the cinnabar of the hard substrate Changhua chicken-blood stone and no Sb in the cinnabar of the Qinghai and Sichuan "chicken-blood stones". The Hg in the Guizhou, Qinghai, and Sichuan "chicken-blood stone" are likely replaced by a small amount of Fe, Ni, Cu and other elements.Through the analysis of energy spectrum and element content of the uncertain minerals in the samples, the cinnabar accompanying with barite can be observed in the Xi'an "chicken-blood stone". This study characterized the mineralogical characteristics of the hard substrate Changhua chicken-blood stone and its similar varieties from mineralogical point of view, which provided basic materials for the identification of chicken-blood stone and its similar varieties.

     

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