AW: [meteorite-list] Classification

[Jörn Koblitz]

Dear Tom,

The reason is rather simple: nickel test is only applicable to iron meteorites. For stony meteorites - about 90% of all meteorites - it would not give clear doubtless results and it even would contaminate the meteorite. In case of iron meteorites, the easiest way to identify the cosmic origin is to etch a blank surface using nitric or hydrochloric acid to see if a Widmanstätten pattern is present. Often - especially in case of medium and coarse octahedrites - one can even see this structure on a cut, untreated surface, because of different mechanical properties of contained kamacite and plessite/taenite. In the rare case, that no Widmanstätten pattern is existant (ataxites or hexahedrites), the nickel test would indeed help to disciminate the cosmic from a terrestrial origin.

Best regards,
Jorn Koblitz


> -----Ursprüngliche Nachricht-----
> Von: Thomas Kingery [mailto:tkingery at webtv.net]
> Gesendet: Mittwoch, 12. Mai 2004 14:57
> An: meteorite-list at meteoritecentral.com
> Betreff: [meteorite-list] Classification
> 
> 
> I am curious why I have never seen anyone mention that they 
> at least did
> a nickel test on an unclassified meteorite they are selling. I realize
> this does not prove it to be a meteorite but does increase the
> possibility.
> Here in Texas  there are a few ranchers and others that state 
> they found
> what they believe to be a meteorite but have never nickel 
> tested or sent
> off to be analyzed
> 
>                             Tom Kingery
>                              Llano,TX 
> 
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