gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1985.049.353.12 Ganomalite from Franklin, New Jersey, and Jakobsberg, Sweden: New Chemical and Crystallographic Data Dunn Pete J. Department of Mineral Sciences, Smithsonian Institution, Washington, DC 20560, USA Peacor Donald R. Valley John W. * Randall Charles A. † Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA

Present address: Department of Geology and Geophysics, University of Wisconsin, Madison, Wisconsin 53706.

Present address: Thomas Road, Rindge, New Hampshire 03461.

 9 1985 49 353 579 582 10 6 1984 Copyright © 1985, The Mineralogical Society 1985 Abstract

Chemical analyses for ganomalite from Franklin, New Jersey, and Jakobsberg, Nordmark, Sweden, imply that Mn is an essential element and that the formula is Pb9Ca5MnSi9O33, with Z = 1 for the hexagonal unit cell. Preliminary crystal structure data confirm that Mn and Ca are ordered, as implied by the chemical analyses. Ganomalite is hexagonal, space group P3, with a = 9.82 and c = 10.13 Å. Occurrences of samples from both localities are described, together with analytical data for macedonite from Jakobsberg.

 Keywords ganomalite Franklin New Jersey USA Jakobsberg Sweden