[meteorite-list] New Gebel Kamil meteorite with Schlieren bands

From: bernd.pauli at paulinet.de <bernd.pauli_at_meteoritecentral.com>
Date: 03 Oct 2010 18:47:00 UT
Message-ID: <DIIE.000000BF00005149_at_paulinet.de>

Hello Tim, Mirko, and List,

As Mirko already pointed out, the schlieren banding will only be seen
after etching (at least slight etching or deep-etch if you prefer that).

Only then will you see these characteristic diffuse streaks (usually of group
IVB ataxites - another reason why Gebel Kamil is classified as "ungrouped").

The image that Mirko provided and one of my slices (from Mirko) clearly
reveal those bands and patches dovetailed into each other and tapering out
irregularly.

Now, when you tilt such polished and etched slices against a light source,
you will notice that bright and matte parts shift alternatingly: the bands
that were bright from one perspective, now appear dull and vice versa.

This oriented sheen has to do with the "alpha + gamma" structure, cooling,
decomposition, (absence of) diffusion, crystallographic orientation, etc.
.. too complicated (for me :-) to explain.

Best "Schlieren"
wishes,

Bernd
Received on Sun 03 Oct 2010 02:47:00 PM PDT