几种具有代表性青田石的矿物学特征初探

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。

Mineralogical Characteristics of Several Types of Representative Qingtian Stone

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,yellowish-brown and yellowish-green） is different,and its grainy texture is mainly caused by the higher content and better crytallization of quartz.