Ian and all,
Foshagite fits, but there are many hydrous calc-silicate minerals.
Powder XRD would be definitive. DHZ is not the best place to look for
unusual minerals. Strunz or the old Dana's Textbook of Mineralogy are
better because they have a chemical index, unlike virtually all modern
mineralogical tabulations that have been published.
Eric
Dear All,
>
>I'm getting in touch with a query about a (presumably hydrous) Ca-Si
>silicate mineral that occurs in retrograde assemblages replacing the
>mineralogy of high-temperature calc-silicate xenoliths in the Bushveld
>Complex, South Africa. The mineral occurs as moderate relief, low
>birefrengent needle-like grains in: a) monomineralic veins cutting
>akermanite-monticellite assemblages; b) in aggregates with diopside,
>calcite and grossular-rich garnet replacing vesuvianite, and c) with
>calcite replacing monticellite. Electron probe analyses give totals of
>~92-94 wt%, and for a nominal 10 oxygens there are 4 Ca, 3 Si and nothing
>much else. From the breakdown textures after vesuvianite I'd thought that
>the mystery mineral may have been xonotlite, but the stoichiometry doesn't
>fit. I've been through DH&Z without any luck, and would be interested in
>hearing any ideas as to the identity of this mineral.
>
>Cheers
>
>Ian Buick
>
>_____________________________________________________________________
>
>Dr Ian Buick Phone: National:
>(03) 9479 2647
>ARC Senior Research Fellow
>Dept. of Earth Sciences International: ###
>61-3-9479 2647
>La Trobe University
>Bundoora, Victoria 3083 Fax: National: (03) 9479 1272
>AUSTRALIA International: ###
>61-3-9479 1272
>
> E-Mail:
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