[meteorite-list] Dronino Preservation

From: jbaxter112_at_pol.net <jbaxter112_at_meteoritecentral.com>
Date: Wed Jan 18 17:31:45 2006
Message-ID: <50719.10.250.10.1.1137623499.squirrel_at_sq04.pol.net>

Hello Berndt, Stefan, et al.,

I was nervous about Dronino but it is a beautiful meteorite so I bought
one of Marcin's slices which has been quite stable for over 6 months now.
I do keep all my specimens at less than 10% relative humidity which really
helps.

Even at very low humidity my Brahin slice became dust and yet rumor has it
that some Brahin specimens are stable. I suspect that the terrestrial
exposure history of a particular specimen plays a significant role in the
variability of rusting; perhaps fracturing allowing moisture into the
interior is another important variable. Preparation technique is
presumably important as well. Too bad there is not a way to test for this
tendency; in its absence I guess the best test is that a reliable observer
has observed a particular individual or slices from a particular
individual over time without visible degradation.


Regards,
Jim Baxter

> Stefan wrote:
>
> "Just watching the slow disintegration of my little 63g Dronino
> individual.
> Not the prettiest way of losing weight...Any chance of preserving it
> from total crumbleation?"
>
> Matteo responded:
>
> "Dronino its a horrible rust meteorite, for the moment the 2th only
> after Campo del Cielo."
>
> Don't forget Nantan...another rust bucket. I had a nice Nantan
> individual that I purchased at a mineral show in Ulm (Germany) in 1999.
> About two years later it had rusted and crumbled almost beyond
> recognition.
>
> Morasko can also be very, very prone to rusting. My little piece from
> ... looks jet-black as if HCL had been poured over a lump of sugar :-(
>
> Luckily I was careful enough because I bought only a small 12-gram
> endcut which I observed rusting away in spite of the silica gel I used
> to protect it.
>
> Dronino is a very difficult candidate because of its large amount of
> sulfides (about 10vol%!). Moreover, its sulfide nodules are usually
> surrounded by Fe hydroxides, ... a fateful combination with regard to
> hard-to-stop rusting :-(
>
> Cheers,
>
> Bernd
>
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Received on Wed 18 Jan 2006 05:31:39 PM PST