湖北通城透锂长石伟晶岩中锂辉石的发现

THE DISCOVERY OF SPODUMENE IN PETALITE PEGMATITE,TONGCHENG,HUBEI CHINA

湖北通城伟晶岩体是我国唯一的以透锂长石为主要锂矿物的锂伟晶岩，而在该伟晶岩中发现首次与透锂长石成因密切相关的锂辉石，该锂辉石呈灰白色-白色，强玻璃光泽．比重为3．12，硬度为6．5～7．0，有平行c轴的纵纹，正交偏光下为二轴晶，负光性。在常温下测得其3个光学主轴的参数为：Ng=1．675。Np=1．667，Nm=1．669，Ng-Np=0．008，2V=60°。锂辉石样品的化学成份ω（B）为：Li2O 7．61％．Al2O3 27．72％，SiO2 63．30％．K2O 0．03％．Na2O 0．19％。CaO 0．05％．MgO 0．11％，FeO 0.21％，MnO 0．35％．H2O^＋ 0．30％，H2O 0．52％，总计100．39％。锂辉石样品的X射线数据为：2．791（100），2．917（52），4．250（61），6．109（51），2．863（16）和4．445（16）与标准锂辉石相吻合。

Pegmatite containing mainly of petalite minerals was only reported in Tongcheng of Hubei province in China. In this paper, it presents the first discovery of spodumene in the Tongcheng pegmatite. The spodumene is of grey to white color, strong glassy in luster, with a density of 3.12, hardness between 6.5～7.0, and with veins parallel c axis. It was optically biaxial positive with Ng=1. 675,Np=1. 667,Nm=1. 669,Ng-Np=0. 008, and 2V= 60°. The analysis of chemical composition of the spodumene showed that ω（Li2O）=7.61%, ω（Al2O3）= 27.72% ,ω（SiO2 ）=63.30% ,ω（K2O） =0.03% ,ω（Na2O） =0.19% ,ω（CaO）=0.05% ,ω（FeO） =0.21%,w（MnO） =0.35%, ω（MgO）=0.11%,ω（H2O^＋） =0.30%, and H2O=0.52%,∑100. 39%. The strongest X-ray diffraction characterized by 2.79（100）,2. 917（52）,4. 250（61）, 6. 109（51）,2. 863（16）, and 4. 445（16）. IR curves of the spodumene are also presented in this paper.