A New Polytype of Taaffeite—A Rare Beryllium Mineral from the Granulites of Central Australia

D. R. Hudson, Allan F. Wilson and Ian M. Threadgold
Department of Geology and Mineralogy, University of Queensland, St. Lucia, Queensland, Australia
Department of Geology and Geophysics, University of Sydney, Sydney, New South Wales, Australia

Summary: Chemical and single crystal X-ray studies have shown the existence of a 9-layer polytype of taaffeite. The parameters of the hexagonal unit-cell are a 5·675 Å, c 41·096 Å (arh 14·085 Å, α 23·24°). The oxide composition of the mineral is Al2O3 71·44, MgO 15·76, FeO 6·78, BeO 5·50%. It is pale olive green, with refractive indices ω = 1·739, ε = 1·735, and a specific gravity of 3·68.

Mineralogical Magazine; September 1967 v. 36; no. 279; p. 305-310; DOI: 10.1180/minmag.1967.036.279.01
© 1967, The Mineralogical Society
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