[meteorite-list] Fake Moldavites

[drtanuki]

Dear Zelimir and List Members,
  The fake moldavite is made from soda-lime glass and
a simple refractive index test is all that is required
to test it.

http://en.wikipedia.org/wiki/Soda-lime_glass

  I and the show owner were unaware of the fake
material being sold as moldavite otherwise the seller
would have been thrown out of the show.

Dirk Ross...Tokyo


--- Zelimir Gabelica <Zelimir.Gabelica at uha.fr> wrote:

> 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 écrit :
> >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Ede 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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