Compositional Segregation and Solid Solution in the Lead-Dominant Alunite-Type Minerals from Broken Hill, N.S.W.

K. J. Rattray, M. R. Taylor, D. J. M. Bevan and A. Pring
Department of Chemistry , Flinders University, GPO Box 2100 Adelaide, South Australia 5000, Australia
Department of Mineralogy, South Australian Museum, North Terrace, Adelaide, South Australia 5000, Australia

Abstract: A study of the composition and unit cell data of a suite of lead-rich minerals of the alunite-jarosite group from the oxidized zone of the ore body at Broken Hill, New South Wales, Australia, has revealed almost complete XO4 (X = As, P, S) solid solution in these minerals at this deposit. The species in the group noted are hidalgoite, hinsdalite, beudantite, segnitite and plumbogummite. These minerals at Broken Hill exhibit a number of growth textures, including oscillatory zoning, colloform banding and replacements. Zoning in these minerals is due to the segregation of Al- and Fe-rich members, and compositions indicate a strong coupling of Fe3+ with AsO43− and AI with PO43−.

Keywords: segregation • solid-solution • hidalgoite • plumbogummite • alunite-type minerals • Broken Hill • Australia

Mineralogical Magazine; October 1996 v. 60; no. 402; p. 779-785; DOI: 10.1180/minmag.1996.060.402.07
© 1996, The Mineralogical Society
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