[meteorite-list] Re: Patina

From: Notkin <geoking_at_meteoritecentral.com>
Date: Fri May 12 14:11:29 2006
Message-ID: <ed619d5803505f0dc34ab4731b20ba22_at_notkin.net>

Gary K. Foote wrote:

> Which is best value wise? Original condition with dirt and natural
> patina or cleaned
> with patina left or cleaned and polished free of patina?


Dear Gary:

This is a very good question, and I suppose many will feel it's a
matter of personal taste.

When we look at meteorites which acquire a beautiful natural patina
such as Canyon Diablo, Gibeon, Henbury, my opinion as a collector of
irons is that the patina adds a great deal to the character of a
specimen. These colors have been slowly acquired over hundreds or
thousands of years, and the irons have taken on something of the
essence of the desert that surrounded them. As I'm sure you know,
Gibeons tend to be ochre; Canyon Diablos tend to have a tan or caramel
color; Henburys are usually reddish-orange. In my view, these patinas
are as unique as the meteorites themselves. If you put a cleaned Taza
and a cleaned Sikhote-Alin next to each other, 9 out of 10 experts
probably couldn't tell them apart without cutting and etching, but
uncleaned they have a distinctly different appearance and character.

The Brenhams that Steve Arnold and Co. have recently found have a
lovely caramel/chocolate patina, and I find it very attractive. During
the Tucson show this year, Steve cleaned one of his smaller individuals
with a wire brush to see how it would look. It happened to be one of
the meteorites that we had found together, and I was hopping around
saying, "No! No! Don't clean it." Had no effect of course : ) It
ended up looking nice, but to my eye natural is better.


Which do you prefer?

Cleaned Gibeon: http://www.aerolite.org/catalogue/gibeon-2606.htm

Natural Gibeon: http://www.aerolite.org/catalogue/gibeon-1015.htm


To be fair, I have to say that in most cases I do prefer Campos that
have been cleaned, and I'd certainly want the dirt removed from any
specimen. I've carefully removed caliche from Odessas, Canyon Diablos,
and Tazas, but left the patina intact. Uncleaned Campos have a muddy
color that's not so appealing, likely because they aren't found in
deserts like most of the specimens mentioned above, and haven't had the
chance to acquire that dry-desert patina.

Some collectors like to see their irons silver and wire brushed. It's a
matter of what appeals to you the most, I guess, but as our friend
Allan Lang observed: "You can always clean an iron, but you can't put
the patina back on."

Wise words indeed.

Careful with that wire brush! : )


Regards,

Geoff N.
www.aerolite.org
Received on Fri 12 May 2006 02:11:21 PM PDT