[meteorite-list] troilite euhedral crystals

From: Zelimir Gabelica <Zelimir.Gabelica_at_meteoritecentral.com>
Date: Sat, 13 Jan 2007 17:37:29 +0100
Message-ID: <5.0.2.1.2.20070113171405.0281a7d0_at_pop.univ-mulhouse.fr>

Hello Dave, Gary, Bernd, Roger, list

Dave, I am glad youthese mentioned euhedral (pyritohedral) troilite crystals.

Well, I formely cut a Sierra Colorada (Argentina, L5) and two of the slices
obtained contained large (almost centimetric) vugs, some making the 3 mm
thick slice hollow!
Looking inside is again really breathtaking.
Several 5 to almost 10 mm (!) euhedral metallic crystals (also pyritohedral
in shape) can be seen, aligned or dispersed, some as quasi isolated single
crystals, onto the vug walls.
One of them is sectioned through cutting and that small cut face (clearly
seen on 2 pictures) indiceted to me, from the typical luster of the cut
section, that these could be schreibersite (also possible, though perhaps
less likely than troilite). See pictures 4741 and 4744.

This is as spectacular as looking into a geode of a terrestrial mineral
(although I have never seen terrestrial schreibersite, if ever it exists,
because phosphides should readily yield phosphates in contact with air).

My friend Roger Warin, not only expert in taking spectacular pictures of
thin sections (see some preceding posts), was also able to realize superb
close-ups of these geodes and "schreibersite" crystals.
I have no web site to store these peictures for the list but I am enclosing
5 of them as attachments for Bernd, Dave, Roger and Gary .

Should perhaps Gary find a way to put them on his URL and send the link to
the list, this wouild be just great!
Thanks!

Pleased to read your comments.

Take care,

Zelimir


A 16:13 13/01/2007 +0000, Dave Harris a ?crit :
>Hi,
>My Mt. Taz definitely has euhedral crystals in the vesicles - unfortunately,
>my binocular microscope only magnifies to about x35 or so and they are very
>small (very sub-mm ) but become apparent when the specimen is tilted and the
>light glints off the faces.
>
>The structure is typically pyritohedral in shape - I am assuming (a
>dangerous thing to do) that these are Troilite xls.
>
>..and I never got a response as to what gases made the vesicular structure!
>
>
>Best
>
>
>
>Dave
>IMCA #0092
>Sec.BIMS
>www.bimsociety.org
>______________________________________________
>Meteorite-list mailing list
>Meteorite-list at meteoritecentral.com
>http://six.pairlist.net/mailman/listinfo/meteorite-list

Prof. Zelimir Gabelica
Universit? de Haute Alsace
ENSCMu, Lab. GSEC,
3, Rue A. Werner,
F-68093 Mulhouse Cedex, France
Tel: +33 (0)3 89 33 68 94
Fax: +33 (0)3 89 33 68 15
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Received on Sat 13 Jan 2007 11:37:29 AM PST