[meteorite-list] Fake Moldavites

From: Jean-Alix Barrat <barrat_at_meteoritecentral.com>
Date: Fri, 21 Dec 2007 11:53:34 +0100
Message-ID: <476B9B2E.9000800_at_univ-brest.fr>

Just for the fun, I can analyze the fakes, for major and trace elements.

Jean-Alix Barrat
Professor of Geochemistry
UBO-IUEM
CNRS, UMR 6538 ("Domaines Oc?aniques")
Place Nicolas Copernic
29280 Plouzan? Cedex


Zelimir Gabelica a ?crit :
> Mike, Bernd, Andi, Michael, all,
>
> Could be interesting to perform some accurate chemical analysis on
> some selected fakes.
>
> Probably the relative amounts of main oxides (SiO2 from 79 to 83%,
> Al2O3 from 8 to 11%, K2O from 2.4 to 3.4%, CaO from 1.4 to 2.7%, or
> MgO from 1.3 to 1.9%, as taken from data given by Heinen, after Bouska
> (1994) for 3 main moldavite deposits - see his book "Tektites,
> witnesses of cosmic catastrophes, p 89) would be similar.
>
> But how about minor oxides (TiO2, MnO or Na2O) ? Not to speak about
> the REE (rare earth elements) that are present in the ppm (part per
> million) range in natural moldavites.
> Could the "fakers" have thought to add in right proportions all these
> REE in right proportion ?
>
> Sure, such an analysis is not easy to perform and is certainly
> expensive and basically nobody among the buyers would have even
> thought to do it on their purchased pieces.
> But I would just be curious about the bulk composition of the fakes.
> Indeed it can be possible that some very different chemical
> composition would also yield such a "nice"" green shade, while this
> green color is probably attanied to in real moldavites because of the
> presence of some minor impurities.
>
> Did someone try to analyze the fakes ?
>
> This being, I agree with Michael, this is a real tragedy for
> collectors as there is probably nothing more to do than to carefully
> look for external characteristics (bubbles, "schlieren"...) on a
> suspected moldavite and further check the purchase date and the
> dealer's name for our older collection pieces.
>
> Good luck and thanks Mike and Michael for their warnings.
>
> Anyway....Merry Christmas to everybody and many happy huntings for the
> New Year to come!
>
> Zelimir
>
>
>
> A 14:16 20/12/2007 -0800, Michael Farmer a ?crit :
>> Yes, these fake Chinese pieces are perfect, with great
>> color and no flaws. That lack of flaws should be the
>> first indication of authenticity.
>> They are melting glass and pouring molds.
>> Michael Farmer
>> --- Andreas Gren <info at meteoritenhaus.de> wrote:
>>
>> > Not to forget, the small bubbles in the real
>> > Moldavites and the "Schlieren"
>> > in the real Moldavites, like the Schlierenbands in
>> > some Ataxites
>> >
>> > Bubbles: http://moldavit.de/foto/fsammlung3.htm
>> >
>> > Schlieren: http://moldavit.de/foto/fsammlung2.htm
>> >
>> > Best regards
>> > Andi
>> >
>> >
>> > Mike wrote:
>> >
>> > They were mostly set in wire as pendants, and when
>> > put side by side, you
>> > could clearly
>> > see them as identical, made in a mold. I have found
>> > one of the same on ebay,
>> > at a very
>> > high price.
>> >
>> >
>> http://cgi.ebay.com/Czech-Moldavite-200-5-Carat-Green-Meteorite-Tektite_
>> >
>> W0QQitemZ200179801535QQihZ010QQcategoryZ3239QQssPageNameZWDVWQQrdZ1QQcmdZVie
>>
>> > wItem
>> >
>> > You can clearly recognize this one is an artifact (a
>> > fake) because the
>> > greenish
>> > color is way too "monotonous" and the grooves too
>> > "regular" !!!
>> >
>> > Bernd
>> >
>
> Prof. Zelimir Gabelica
> Universit? de Haute Alsace
> ENSCMu, Lab. GSEC,
> 3, Rue A. Werner,
> F-68093 Mulhouse Cedex, France
> Tel: +33 (0)3 89 33 68 94
> Fax: +33 (0)3 89 33 68 15
>
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Received on Fri 21 Dec 2007 05:53:34 AM PST