gsminmag Mineralogical Magazine Mineralogical Magazine 0026-461X Mineralogical Society 10.1180/minmag.1963.033.261.06 Some Natural Analcime Solid Solutions Wilkinson J. F. G. M.Sc., Ph.D. Department of Geology, The University of New England, Armidale, N.S.W. 6 1963 33 261 498 505 Copyright © 1963, The Mineralogical Society 1963 Summary

Chemical, optical, and X-ray data are presented on three analcimes from a differentiation sequence, olivine-theralite to analcime-tinguaite; compared with the ideal analcime composition, they reveal replacement of NaAl→Si. Optical and X-ray data on these minerals accord reasonably well with analcimes possessing similar compositions, and synthesized in the sub-solidus region in the NaAlSiO4-NaAlSi3O8-H2O system.