[meteorite-list] Is Brahin a ruster ?

From: Martin Altmann <Altmann_at_meteoritecentral.com>
Date: Tue Feb 8 08:45:02 2005
Message-ID: <000601c50de4$f1d80d60$045f9a54_at_9y6y40j>

Yes indeed one never can be sure.
First one can't make any individually forecast for a single piece, the
tendency to rust is different from specimen to specimen from one and the
same find, obviously it depends how much chlorine it absorbed. Only the
general tendency may predicted.
A friend of mine had an etched Campo, completely untreated and not
stabilized, which was stable like wood for 15 years (thus not a
representative of the so called "New" Campos), while the gross of the Campos
I heard of from my collectors rusted away like hell, no matter whether "New"
or old.
Otherway round, I met once on a show a seller, who had a large box full of
Gibeons, all despite being oiled with messy rust traces.
I for my own keep cutting material for a certain time in quarantine to see,
if a coating will be necessary after preparation and recommend in general to
the new collectors, first to be aware, that every iron can rust and second,
to keep the finger away on the beginning from such problematic irons like
Campo, Nantan or Dronino, although they are by far the cheapest meteorites,
to avoid frustrations.

Now with Brahin, I wanted to line out, that a carefully sealed one, even if
it's not so perfect pretty looking, would be the best and I wanted to share
my experience with the both main supplier of Brahin in US-ebay, as Brahin
will be always the first choice for a beginning colletor, if he/she wants to
own a pallasite, as it is so silly cheap at the moment. (Anyone to remember,
how the Brahin price was 15 years ago?) :-).

Thus again, those from Afanasjev cometshop were extremely stable and from
Koutyrev finmet I heard only the best.

Cheers!
Martin

PS: Most stable pallasite I ever had, unstabilized, uncoated, stored without
dessicant
was Imilac. Also a beauty!
Cheapest and best available at the moment through Sergej Vassiliev & Moritz
Karl. Guess something around 15$/gm for translucent slices.

PPS: I had a tiny Admire from Buehler many years ago. It's still in good
condition.

----- Original Message -----
From: "J?rn Koblitz" <koblitz_at_microfab.de>
To: "Martin Altmann" <Altmann_at_Meteorite-Martin.de>; "Lars Pedersen"
<lbp_at_privat.tdcadsl.dk>; <meteorite-list@meteoritecentral.com>
Sent: Tuesday, February 08, 2005 2:04 PM
Subject: AW: [meteorite-list] Is Brahin a ruster ?


Hi List,

back in the 1980s, I got a large, beautiful Admire slice. I kept it at low
humidity and also added corrosion inhibitor to the bag in which the slice
was wrapped in. During the first 10 years I checked for signs of rust from
time to time. It was okay, no rust, very stable. So, I kept it alone (same
storage conditions) until one year ago, when I look at it again. Well, the
pallasite was in the state of disintegration, heavily rusted, olivines
pressed out of the metal grid. What I want to say is, that even after so
long time of stability, one can never be sure. I think, one has to check the
state of such a known ruster more often. If any sign of rust, especially
swallowing of olivine grains, one has to start corrective actions
immediately (e.g. neutralization of acids, drying...). Rusting is a
self-accelerating process, once it has started. If a meteorite is known as a
ruster (like Brahin, Brenham, Admire), be very careful!
Received on Tue 08 Feb 2005 08:49:00 AM PST