青田石品种的分类及其鉴别特征研究

目前,青田石约有100余品种。X射线粉末衍射和化学成分分析表明,依据其矿物组成,青田石可分为叶蜡石型、地开石型、伊利石型和绢云母型。其中,叶蜡石型又可细分为纯叶蜡石亚型、高Fe叶蜡石亚型、高Al叶蜡石亚型和高Si叶蜡石亚型;按照其产地,青田石可分为＂封门石＂＂周村石＂＂北山石＂＂山炮石＂等。不同产地青田石的鉴别特征与其矿物组成有关。通过脆裂性、＂Fe染现象＂、次要矿物、多型特征、密度等鉴别特征可区分不同的青田石品种。

Study on Classification and Identification Characteristics of Varieties of Qingtian Stone

Recently ,the varieties of Qingtian stone are more than a hundred.According to the mineral components ,the varieties of Qingtian stone could be divided into the pyrophyllite-type ,the dickite-type ,the illite-type and the sericite-type .The pyrophyllite-type Qingtian stone could be further divided into the pure-pyrophyllite-type ,the multiiron-pyrophyllite type ,the multialuminium-pyrophyllite-type andthe multisilicon-pyrophyllite-type . According to the locality ,the varieties of Qingtian stone could be divided into ＂Fengmen stone＂ ＂Zhoucun stone＂ ＂Beishan stone＂ and ＂Shanpao stone＂,etc .The identification characteristics of Qingtian stone fromthe different localities are relatedto the mineral components .The different varieties of Qingtian stone could be distinguished by the brittle ,＂iron-stained phenomenon＂,secondary mineral ,pleomorphism,density and so on.