[meteorite-list] Fusion Crust on Irons / Blued metal

From: Herbert Raab <hraab2006_at_meteoritecentral.com>
Date: Tue, 05 Dec 2006 02:00:25 +0100 (MET)
Message-ID: <1165280425.4574c4a9e0af9_at_webmail.aon.at>

> Anyone have an artificially blued meteorite to post?

Here is an image of two specimens from my collection:

  http://www.astrometrica.at/Images/SikhoteCrust.jpg

(Sorry, the image is not perefect. But hey, it's 1:30 AM here...!)

The top specimen looks like most of the pieces available in the past
years. Honetsly, I don't think that it's fresh fusion crust. At the left
(and more so on the back), this specimen seems to be scarred by
rust. But the rust is gone - hardly any trace of it now. I bet that
anything that would remove the rust also would remove the fragile
fusion crust. So I suppose that this (and most specimens available
today, and thus most others I have) was blued, after the rust has
been removed somehow.

The bottom specimen still has it's original crust. Like the wonderful
specimen shown by Martin, it has a thin rust film in the thumbprints.
I suppose that minor rust (though not yet enough to scarr over the
surface) formed quickly after the meteorites have impacted the humid
siberian soil. So anything that has it's original fusion crust must have
been recovered very soon after the fall. Note that the fusion crust of
the lower specimen is less shiny, but more bluish, than on the upper
piece.

The differenc is more visible in the original specimens than on the
image. If you have seen both types, it's not difficult to tell them
apart.

By the way: And I have another, soewhat larger inidviual with original
crust. Any yes, the crust *is* thick enough to chip in some places,
as seen here:

  http://www.astrometrica.at/Images/SikhoteChip.jpg

Cheers,
  Herbert


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Received on Mon 04 Dec 2006 08:00:25 PM PST