Hello,
studying glaucophane + cpx + grt-bearing rocks
from Syros (Greece) and Ile de Groix (France), I
recently came across a tiny but outstanding
mineral that I am ashamed to admit not to be able
to identify. It occurs in several samples from
both localities, but I never saw it so clearly in
other rock types (at least I don't remember). I'm
attaching three photographs of it and would be
very grateful for a suggestion.
It is brownish-red to orange, slightly pleochroic
with relatively high relief and occurs typically
as very thin lamellae (inclusions?) in white
micas, apparently parallel to the cleavage.
Locally it also ocurs in garnet. It is so thin
that the optical properties interfere strongly
with the mineral hosts. I'm afraid that for the
same reason microprobe analyses wouldn't be
conclusive either. Normally I would neglect it as
a "iron hydroxyde", but its attractive appearance
in these sections (and the fact that it seems
enjoy such mineral assemblages) prevents me from
doing so.
Thanks a lot for any suggestions!
Have a nice end of the year, and a good new one!
Cheers,
Pavel
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Pavel PITRA
Geosciences Rennes email: [log in to unmask]
Université Rennes 1 tel: (++33) 2.23.23.65.06
Campus de Beaulieu - Bat. 15 fax: (++33) 2.23.23.60.97
F - 35 042 RENNES CEDEX
FRANCE http://www.geosciences.univ-rennes1.fr/
http://www.geosciences.univ-rennes1.fr/rubrique.php3?id_rubrique=71
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