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 Post subject: moldavite and telling it from fakes
PostPosted: Tue Dec 24, 2013 3:33 am 
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hello folks. I am stumped. I need a way to tell moldavite from a glass fake, we buy around a 2 pounds a year of moldavite rough to set in wire wrap jewelry that we make, and we are just lately hearing of the fake stuff, and being accused of selling it, too. We buy all our stones in Quartzite or Tucson at the gem shows from folks from the Chech republic, Russia or Germany. It has all the visual earmarks I have read about, the swirls and bubbles, sharp definition in the surface patterns, the color matches the stuff I have seen in museums and on line, there are no repetitive shapes, or mold marks, it is not shiny or melted looking. But is there a way to test and tell moldavite from glass, since moldavite is itself a glass? I have been researching online, and getting more confused. Please help!! would S.G. tell the difference ? or refractive index? or density or hardness? I get new values for moldavite for these tests on every website I go to, and I have not been able to find the values for green glass to compare with, aauuuggghhhhh, confusion reigns right now !! :?


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 Post subject: Re: moldavite and telling it from fakes
PostPosted: Tue Dec 24, 2013 8:27 am 
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well a gemologist can separate Moldavite from Man Made Glass by the observation, appearance, magnification, RI, SG, and by its optical characteristics....(and other Identification Process)

Moldavite is natural glass so it has common characteristics with man made glass, like rounded or elongated Gas bubble. its not 100% sure to rely on it, other Identification Characteristic is needed to identify the stone.

in gemology world sometimes identifying simple or cheap stuff is more challenge than Ruby/Sapphire/Diamond....

if you have any data like SG, RI, Picture,.... of your sample you can share here so people can help.
but to be sure you must find a reliable source, sometimes efforts & cost of identification does not worth it, but if you want to be 100% sure you can send some samples from the lot you are going to buy to a reputable Gem Lab.

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 Post subject: Re: moldavite and telling it from fakes
PostPosted: Tue Dec 24, 2013 6:08 pm 
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Use specific gravity.
Measure the value of a known sample you which to duplicate to two decimal places.
You should want to buy material having that same SG value (+/- 0.01) and having the same color, and texture, if rough.


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 Post subject: Re: moldavite and telling it from fakes
PostPosted: Wed Dec 25, 2013 1:42 am 
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thank you both. unfortunately, there would be no way to have it tested before purchase at the gem shows, I was looking for a relatively easy way to test it at the show, other than by the visual characteristics, which is how we have been doing it. I have never done specific gravity, just read about it, and the numbers for moldavite are almost identical to green glass, and according to what I read, the density of the bubbles in the moldavite will change the specific gravity... I do not even know how to do the test to see what they are talking about, any explainations or other ideas would be gratefully recieved , :)


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 Post subject: Re: moldavite and telling it from fakes
PostPosted: Wed Dec 25, 2013 3:57 am 
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learn how to test S.G, it aint hard, and take Bills advice. What more needs to be said!
You at least then, can refute your critics!


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 Post subject: Re: moldavite and telling it from fakes
PostPosted: Thu Jan 02, 2014 12:12 pm 
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Dr Hannemann's advice is sound.

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 Post subject: Re: moldavite and telling it from fakes
PostPosted: Thu Jan 02, 2014 5:15 pm 
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Refresh me.
What is the SG of moldavite and would that definitively separate them from other glasses, natural and man made?


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 Post subject: Re: moldavite and telling it from fakes
PostPosted: Thu Jan 02, 2014 5:37 pm 
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Natural Glass SG: 2.36 -/+ .04
unlike man made glass which goes up to 4.5

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 Post subject: Re: moldavite and telling it from fakes
PostPosted: Fri Mar 18, 2016 4:01 am 
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Index of refraction (RI) of moldavites is between 1.46 and 1.54
Specific gravity (SG): 2.32 – 2.4

Source and guide how to tell real / fake moldavites


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 Post subject: Re: moldavite and telling it from fakes
PostPosted: Fri Mar 18, 2016 11:23 am 
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We missed it the first time around, but the easy distinguishing feature is the wires of 'lechatelierite' (which as far as I can tell is just pure or near-pure silica glass). See http://www.gia.edu/gems-gemology/spring ... tural-fake

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 Post subject: Re: moldavite and telling it from fakes
PostPosted: Wed Mar 23, 2016 10:27 am 
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Stephen Challener wrote:
We missed it the first time around, but the easy distinguishing feature is the wires of 'lechatelierite' (which as far as I can tell is just pure or near-pure silica glass). See http://www.gia.edu/gems-gemology/spring ... tural-fake


Yes. And another great indicator of authenticity are schlieren (inhomogenities in moldavites). Unfortunately this indicator is usable only for faceted moldavites.


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