Pyrosmalite in the Broken Hill Lode, New South Wales1

F. L. Stillwell and John McAndrew
Melbourne, Australia
1Published by permission of the Commonwealth Scientific and Industrial Research Organization.

Summary: Pyrosmalite is a widespread, though very limited, constituent of the Broken Hill lode, and is formed by the hydration and chlorination of the manganeseiron silicates. It is altered in contact with galena and eventually disintegrates into a mat of very fine fibres. The pyrosmalite varies substantially in ratio of Mn/Fe, and two specimens from the rare vughs and fractures gave on analysis ratios of 1·96 and 0·71. The refractive indices decrease slightly with increasing amounts of manganese and water, with a simultaneous small increase in the unit-cell dimensions. The name pyrosmalite is retained for the mineral species in accord with its earlier usage and its recent limitation to the iron-rich variety of an isomorphous series is not endorsed.

Mineralogical Magazine; March 1957 v. 31; no. 236; p. 371-380; DOI: 10.1180/minmag.1957.031.236.04
© 1957, The Mineralogical Society
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