[meteorite-list] Troilite in a pallasite? Why are the crystals so small?

From: Graham Christensen <majorvoltage_at_meteoritecentral.com>
Date: Thu Apr 22 09:54:06 2004
Message-ID: <F156YHkidcDjoYAPNXR00026cd4_at_hotmail.com>

Hello meteorite list and all,

I have a 27 gram Brahin pallasite (not etched) that has what looks like a
troilite inclusion. The inclusion is sort of greyish-brown and darker than
the surrounding metal and it appears to have a very fine grainy texture when
observed at 10x magnification. Is this troilite (FeS)? It is very
irregularly shaped compared to the round inlusions found in iron meteorites
and it has many closely packed shards of olivine as opposed to the larger
crystals outside of it. It measures approximately 15mm by 10mm.

I have seen it before in pictures of Brahin on the net and have read a
little about troilite inclusions but I couldn't find very much information.
I was wondering, why are the olivine crystals within the inclusion so small
relative to the crystals in the surrounding metal and why are they so
closely packed together? Also, are there other pallasites with inclusions
like these or are they unique to Brahins?

Any information would be helpful, thanks.
************************************************************
Graham Christensen
majorvoltage_at_hotmail.com
http://www.geocities.com/aerolitehunter


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Received on Sun 17 Feb 2002 04:55:31 PM PST