[meteorite-list] Rainbow effect in an specimen of NWA 4478 Lodranite

From: Mendy Ouzillou <ouzillou_at_meteoritecentral.com>
Date: Mon, 23 Apr 2012 22:15:07 -0700
Message-ID: <02c701cd21d9$36dfaa20$a49efe60$_at_com>

Dear list members,

I received, just today, two Lodranite specimens: an 11.42g end-cut of NWA
4478 and a 9.71g end-cut of NWA 6075. Both specimens are beautiful and the
NWA 6075 exhibits an interesting shimmer effect. However, when I looked at
the face of the NWA 4478, I was shocked to see what can only be described as
a rainbow about 2mm x 3mm (see image in link, will try to get better one up
in the next few days).

http://www.meteoritesusa.com/blog/nwa-4478-lodranite-mystery-rainbow-feature
/
Now the first thing that came to mind is that some oil was trapped in the
structure and created the thin-film physical effect (think oil slick). On
further inspection, there were no other areas that displayed the same effect
though there are similar areas where oil could get trapped. I remembered
seeing something similar on the www.meteorites.com.au website in an Al
Mahbas specimen, but this looks distinctly different.
Oil contaminant or a genuine unusual feature in this lodranite - help me
solve the mystery.

Thank you and any information provided to help me solve the mystery will be
used in any updates to the blog post.

Mendy
Received on Tue 24 Apr 2012 01:15:07 AM PDT