[meteorite-list] Fake Moldavites

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Fri, 21 Dec 2007 02:13:49 -0600
Message-ID: <015e01c843a9$6b1ee520$b64fe146_at_ATARIENGINE>

Hi, Zelimir, List,

The easiest, though not conclusive, test would be
to have a jeweler or gem collector measure the index
of refraction of the suspected Moldavite. The index
of refraction for Moldavites is 1.46 to 1.54; for
man-made glasses, it's 1.52 to 1.55. If every Moldavite
in a selection was over 1.51 or 1.52, I'd be suspicious
of them. The fakers are unlikely to vary the glass density
for every individual fake. If they're all exactly the same,
they're almost certainly fakes. Most jewelers and gem
dealers have refractometers; testing is quick (and cheap).


Sterling K. Webb
-------------------------------------------------------------------
----- Original Message -----
From: "Zelimir Gabelica" <Zelimir.Gabelica at uha.fr>
To: "Michael Farmer" <meteoriteguy at yahoo.com>; "Andreas Gren"
<info at meteoritenhaus.de>; <bernd.pauli at paulinet.de>
Cc: <meteorite-list at meteoritecentral.com>
Sent: Friday, December 21, 2007 1:50 AM
Subject: Re: [meteorite-list] Fake Moldavites


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 03:13:49 AM PST