[meteorite-list] Strange Allende inclusion

From: Bernd Pauli HD <bernd.pauli_at_meteoritecentral.com>
Date: Thu Apr 22 09:50:27 2004
Message-ID: <3CBD94A7.78B51669_at_lehrer1.rz.uni-karlsruhe.de>

Jay wrote:

> I was looking over an Allende slice from my collection last night with
> a 10x loupe and notice quite a large metal flake (well large for Allende
> and it is visible to naked eye) and it looked sort of gold in color. I was
> wondering is this normal for Allende or could it be from the saw? Does
> not look like rust but could be oxidized iron.

Pierre responded:

> There is more sulfide than metal in Allende
> (troilite mostly) so gold color should be it


Hello Jay, bonjour Pierre, hello List,

... unless it is awaruite (ca. 71 wt% Ni), a high-nickel mineral
(Ni3Fe) but this is very improbable as awaruite usually occurs
on a micrometer-scale in Allende.

A large "metal" flake is also very improbable as Pierre has already
stated because there is hardly more than about 0.5 weight percent
m e t a l l i c FeNi in Allende.

*IF* it is some sulfide, it may be pentlandite (Fe,Ni)9S8 and *IF*
it is troilite, ... are you sure you are looking at an Allende specimen
instead of having an Axtell piece*? Axtell and Allende have often
been confounded because they look similar (at least at first sight).

* most of the r a r e sulfide in Axtell is troilite because Axtell
  is described as having escaped a high degree of sulfidation


Best wishes,

Bernd
Received on Wed 17 Apr 2002 11:28:39 AM PDT