AW: [meteorite-list] Sweaty Fingers, Chlorides, and Chondrites

[Jörn Koblitz]

Dear Stephen,

Thank you for your interesting (and important) questions, regarding preservation of chondrites (or more general: stony meteorites). I try to answer them from a scientific point of view:

> 1.  Can one easily do more than just preventing future assaults from
> external moisture and fingerprint chemicals?

There are not so many ways. The best way is, just to store them in a dry environment, ideally with relative humidity <40%, better <20%. Use silica gel as desiccant. Important is to change the desiccant from time to time. Don't touch interior parts with bare hands as salt will get on the specimen which will lead to first corrosion.

> 2.  Will long soaks in anhydrous alcohol help individuals, and polished slices?

It does only help if the specimen got wet before. Then, it can help to quickly pull out the water. Otherwise (with a dry specimen) it can even hurt as alcohol is hygroscopic (it will attrack water from the air humidity). Use alcohol only in combination with a postbake in an oven at about 80 deg. C. DONT DO such things with fresh (observerved falls) carbonaceous chondrites like CMs or CIs. The alcohol will remove pristine organic compounds and the temperature can already alter such meteorites.

> 3.  Has anyone successfully used Steve Schoener's iron stabilization formula for individuals and polished 
> slices of ordinary chondritis (i.e., a mix of water, alcohol, and NaOH)?

NEVER use any chemicals, lacquers, solvents, inhibitors, rust removers etc. on (valuable) stony meteorites!!!! All such agents will very likely alter the meteorite. Such a treated meteorite is LOST to science!!! And: if such treatments have been done and this is not known to the scientist who will study/analyse such a meteorites in the future, it creates lots of confusion, puzzling question on measurement results and additional investigations and at the end lot of wasted time.

So, don't even consider doing such things to stony meteorites - just keep them dry and prevent contamination, including fingerprints, dust, etc.!

Best regards,
Jörn Koblitz / MetBase


> 4.  Does anybody know of a good online sources where an 
> average Joe can
> purchase anhydrous alcohol?


> -----Ursprüngliche Nachricht-----
> Von: Stephen McMann [mailto:stephen_mcmann at hotmail.com]
> Gesendet: Montag, 20. Dezember 2004 17:37
> An: meteorite-list at meteoritecentral.com
> Betreff: [meteorite-list] Sweaty Fingers, Chlorides, and Chondrites
> 
> 
> Dear List,
> 
> Over the past few years there has been much discussion about 
> preserving
> irons, but little discussion about rust prevention in 
> ordinary chondrites.
> However, chondrites can of course suffer from the same 
> problems as irons,
> presumably exacerbated by the same culprits (internal 
> moisture, internal
> chlorides, fingerprints from previous owners, etc.).  Unfortunately,
> chondritis tend to be more complex chemically and so I'm not 
> certain about
> how to deal with these problems in a way that gives display 
> specimens long,
> stable lives.
> 
> Here are some naïve questions:
> 
> 1.  Can one easily do more than just preventing future assaults from
> external moisture and fingerprint chemicals?
> 
> 2.  Will long soaks in anhydrous alcohol help individuals, 
> and polished
> slices?
> 
> 3.  Has anyone successfully used Steve Schoener's iron 
> stabilization formula
> for individuals and polished slices of ordinary chondritis 
> (i.e., a mix of
> water, alcohol, and NaOH)?
> 
> 4.  Does anybody know of a good online sources where an 
> average Joe can
> purchase anhydrous alcohol?
> 
> Sincerely,
> Stephen McMann
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