Ganophyllite from Franklin, New Jersey; Pajsberg, Sweden; and Wales: New Chemical Data

Pete J. Dunn, Donald R. Peacor, Joseph E. Nelen and Robert A. Ramik
Department of Mineral Sciences, Smithsonian Institution, Washington, DC 20560, USA
Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA
Department of Mineral Sciences, Smithsonian Institution, Washington, DC 20560, USA
Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario, Canada

Abstract: Ganophyllite from Franklin, New Jersey, Pajsberg, Sweden, and the Benallt Mine, Wales, has been chemically reinvestigated. Twelve new analyses confirm the general structure of Kato (1980) and yield the tentative formula (K,Na,Ca)2Mn8(Si,Al)12(O,OH)32(OH)4·8H2O. There is little solid solution among octahedral cations, and the Si:Al ratio is nearly constant at 10:2. Ca and (Na + K) are apparently differentiated, but all examined ganophyllites are K-rich. Much of the water content is loosely bound and the upper limit of water content is not well defined. Ganophyllite is relatively invariant in chemical composition from locality to locality.

Mineralogical Magazine; December 1983 v. 47; no. 345; p. 563-566; DOI: 10.1180/minmag.1983.047.345.18
© 1983, The Mineralogical Society
Mineralogical Society (www.minersoc.org)