我国首次发现原生——自然硅

FIRST DISCOVERY OF PRIMARY NATURAL SILICON IN CHINA

本文对自然硅进行了矿相学、矿物学研究。该矿物产于福建某地矽卡岩型硫、多金属矿床中。自然硅呈亮灰银白色、强金属光泽。性脆。镜下呈浑圆粒状、乳滴状。均质。实测比重d=2.368。硬度H_M=6.76。反射率 R 470nm 37.08;546nm 33.44;589nm 31.27;650nm 29.96。经扫描电镜能谱分析、电子探针分析,Si 99.87％～99.94％。含少许Al、Ca、Fe机械混入物。X射线粉晶分析,主要X射线粉晶谱线:3.155(100),1.927(93),1.642(60),1.361(17),1.248(25)。等轴晶系。晶胞参数a=0.544nm。Z=8。空间群:O_h^7-Fd3m。 自然硅根据X射线衍射分析数据及化学成分定名,它的发现具有重要的地质意义和经济意义。

Natural silicon, dealt with in the present paper with respect to its ore microscopy andpetrology, occurs in some sulfur-rich multi-metallic deposits of skarn type. The specimen oftenshows silver-white colour, strong metallic luster, and brittleness, with a specific gravity of 2.368and a hardness of 6.76. It is homogeneous, perfectly round and milk-droplike in appearance un-der reflecting microscope. The reflectivities R are 470nm 37.08, 546nm 33. 44, 589nm 31. 27 and650nm 29.96. A combination of SEM and EPA anglyses revealed that Si accounts for 99.87%-99.94% of its composition while the physical mixture of Al, Ca, and Fe is seldom found. The pow-der diffraction data obtained by X-ray diffraction analysis include powder patterns [3.155(100),1.927(93), 1. 642(60), 1. 361(17), and 1. 248(25)], thus belonging to the isometric system. Unit cellparameter: a = 0.547nm, Z= 8. Space group: O_h^7-Fd3m. A comparison of the X-ray diffraction analysis data on the silicon in question with those ofman-made single-crystal silicon, confirmed no compositional and textural differences betweenthese two minerals. That is, the former is reasonably named natural silicon. Its discovery, to a certain extent, is of economic and geological significance.