gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1978.042.321.11 Manganoan Ilvaite from Broken Hill, N.S.W. Ban Ban, Queensland, Australia Plimer I. R. University of New South Wales, P.O. Box 334, Broken Hill, N.S.W. 2880 Ashley P. M. Minerals Department, Esso Australia Ltd., G.P.O. Box 4047, Sydney, N.S.W. 2001 3 1978 42 321 85 88 16 5 1977 1 8 1977 Copyright © 1978, The Mineralogical Society 1978 Summary

Manganoan ilvaite forms as an early retrograde metamorphic phase from calcic rhodonite in the polymetamorphosed Pb-Zn sulphide/manganese silicate rocks at Broken Hill and from grossular-andradite in a skarn at Ban Ban. Ilvaite exists as a probable metastable phase into which Mn is apparently strongly partitioned. The manganoan ilvaites analysed contain up to 13·5 % MnO substituting for FeO and this substitution shifts the 020 peak.