Marshite-Miersite Solid Solution and Iodargyrite from Broken Hill, New South Wales, Australia

P. W. Millsteed
Faculty of Applied Science University of Canberra, PO Box 1 Belconnen, A.C.T. 2616 Australia

Abstract: Microprobe analysis of marshite and miersite from Broken Hill, Australia, demonstrate extensive solid solution between the end-members CuI and AgI, indicating the possibility of a complete solid-solution series. Unit-cell parameters increase from 6.054 Å for marshite to 6.504 Å for miersite, closely following Vegard's Law. The Cu content of iodargyrite is generally below the limit of detection, but one zoned crystal contained 0.28 wt.% Cu. Crystallization of either miersite or iodargyrite at Broken Hill appears to be dependent upon the local availability and ratio of copper, silver and iodine ions.

Keywords: marshite • meirsite • iodargyrite • Broken Hill • solid solution • copper • silver

Mineralogical Magazine; August 1998 v. 62; no. 4; p. 471-475; DOI: 10.1180/002646198547846
© 1998, The Mineralogical Society
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