福建寿山牛蛋石的矿物学研究

Mineralogical Study on Cattle-Egg Stone from Shoushan County,Fujian Province

对采自福建省寿山溪流域的黄色和黑色牛蛋石样品进行了系统的矿物学研究。采用XRD,SEM,EDS和全岩化学分析,分别对样品的风化皮(俗称"石皮")、基体(俗称"石肉")和核部(俗称"石心")进行了测试。结果表明,不同颜色牛蛋石样品的不同部位皆以叶腊石为主要成分,并以叶腊石的单斜和三斜两种多型共存,其平均晶体结构化学式为Al4.04[Si7.89Al0.11O20](OH)4;其叶腊石集合体呈无定向排列,风化皮中叶腊石单晶的粒度略大于基体中的。两种牛蛋石样品的致色元素为Fe3+离子;黑色样品中不含硬水铝石,而黄色样品中则含有硬水铝石。

The systematic mineralogical studies are worked on the yellow and black cattle-egg stone samples from Shoushan rivulet of Fujian Province. The parts of the weathering skin （popularly called ＂skin of the stone＂）, basal part （popularly called ＂flesh of the stone＂） and core part （popularly called ＂heart of the stone＂） of the cattle-egg stone samples are tested by XRD, SEM, EDS and bulk-rock analysis respectively. It indicates that the different parts of the cattle-egg stone samples in different colours all mainly compose of pyrophyllite,coexisted by two kinds of polytype of monoclinic and triclinic pyrophyllite, and the average crystal structural formula is Al4.04[Si7.89Al0.11O20]（OH）4. The aggregation of pyrophyllite arranges with no direction, and the crystal size of the single pyrophyllite crystal in the weathering skin is a little bigger than that in the basal part. The colour of the two kinds of the samples are caused by Fe^3＋ cation. What＇s more, the black sample contains no diaspore, while the yellow one contains it.