秋田県釈迦内鉱山産の雲母粘土鉱物の一試料

抄録

A specimen of the so-called ill-crystallized sericite was found associated with the Kuroko ore body of the Shakanai mine. The specimenypgives a 10.3 Å reflection and higher orders, but the hkl reflections are extremely weak and broad. Although the specimen is an interstratified mineral of mica with its expandable layers, the X-ray pattern clearly differs from those of 1 Md mica and the common interstratified minerals. The infra-red, DTA and electron diffraction data are similar to those of a mica clay mineral with 2M polymorph. Chemical composition: SiO₂ 47.53%; Al₂O₃ 37.40%; Fe₂O₃ 0.00%; MgO 0.47%; CaO 0.19%; Na₂O 0.34%; K₂O 7.33%; H₂O⁺ 5.32%; H₂O^-1.47%; Total 100.05%.