gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1976.040.316.07 Derivative Structures Based on the Alunite Octahedral Sheet: Mitridatite and Englishite Moore Paul Brian Department of the Geophysical Sciences, The University of Chicago, Chicago, Illinois 60637, USA 12 1976 40 316 863 866 24 2 1976 7 4 1976 Copyright © 1976, The Mineralogical Society 1976 Summary

It is proposed that mitridatite and englishite contain octahedral sheets of the alunite type and that their formulae are [Ca6(H2O)3(PO4)2][Fe3(OH)6(PO4)(PO3OH)]3 and [K2Na(H2O)4Ca4·5 (PO3OH)3][Al3(OH)6(PO4)(PO3OH)]3 respectively.