[meteorite-list] Fake Moldavites

[Jean-Alix Barrat]

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 Océaniques")
Place Nicolas Copernic
29280 Plouzané Cedex


Zelimir Gabelica a écrit :

> 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

> Université 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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