A Hydromuscovite from the Shakanai Mine, Akita Prefecture, Japan

Susumu Shimoda
Geological and Mineralogical Institute, Faculty of Science, Tokyo University of Education, Tokyo, Japan

Abstract: A hydromuscovite in association with gypsum and anhydrite was collected from the Shakanai mine, Akita Prefecture, Japan. Chemical composition: SiO2 47·14%; TiO2 0·34%; Al2O3 37·09%; Fe2O3 0·49%; MgO 0·83%; CaO 0·57%; Na2O 0·35%; K2O 7·10%; H2O+ 5·18%; H2O 0·99%; P2O5 0·01%; total 100·09%. Differential thermal and i.r. absorption analyses were similar to those of hydromuscovite. The X-ray diffraction pattern differed clearly from those of the 1M and/or 2M1 polymorphs and it was similar to that of the 2M2 polymorph, which is known to occur in lepidolites.

Clays and Clay Minerals; December 1970 v. 18; no. 5; p. 269-274; DOI: 10.1346/CCMN.1970.0180505
© 1970, The Clay Minerals Society
Clay Minerals Society (www.clays.org)