几种具有代表性青田石的矿物学特征初探
Mineralogical Characteristics of Several Types of Representative Qingtian Stone
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摘要: 对封门矿区七个不同品种的青田石(“封门青”“金玉冻”“黄金耀”“朱砂”“水草”“紫罗兰”“三彩”)样品进行X射线粉末衍射、红外光谱、激光诱导离解光谱仪等测试,对其主要矿物组成,矿物组合及颜色成因进行了分析探讨。结果显示,“封门青”和“金玉冻”均为成分较纯的叶蜡石,属于叶蜡石型青田石;“黄金耀”的矿物组合为伊利石+少量叶蜡石,属于伊利石型青田石;“朱砂”的矿物组合为叶蜡石+石英+赤铁矿+高岭石,属于叶蜡石型青田石;“紫罗兰”的主要矿物组成是叶蜡石,属于叶蜡石型青田石,其紫色花星成分可能为贫铁蓝线石;“三彩”的主要矿物组成为叶蜡石,但其三个不同颜色(灰色,土黄色,黄绿色)部分的矿物组合不同,石英的质量分数较高且结晶较好是“三彩”显颗粒感的主要原因。Abstract: This paper attempts to explore the major mineral component,mineral combination and colour genesis of seven types of representative Qingtian stone(“Fengmenqing”“Jinyudong”“Huangjinyao”“Zhusha”“Shuicao”“Ziluolan”“Sancai”)by using X-ray powder diffraction,infrared spectrometer and LIBS.The results show that“Fengmenqing”and“Jinyudong”belong to pyrophyllite-type Qingtian stone.“Huangjinyao”belongs to illite-type Qingtian stone,whose mineral combination is illite with a small amount of pyrophyllite.“Zhusha”belongs to pyrophyllite-type Qingtian stone,whose mineral combination is pyrophyllite,quartz,hematite and kaolinite.“Ziluolan”belongs to pyrophyllite-type Qingtian stone,whose purple parts may be dumortierite.The major mineral component of“Sancai”is pyrophyllite,but the mineral combination of its parts of three colours(gray,yellowishbrown and yellowish-green)is different,and its grainy texture is mainly caused by the higher content and better crytallization of quartz.