[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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