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 Post subject: Garnet simulant in Tanzania
PostPosted: Mon Oct 02, 2017 12:14 am 
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My friend Florian le Goff stumbled upon some very convincing and interesting garnet simulant in Tanzania. The simulant rough had been tumbled in order to look like your typical alluvial rough.
I know at least one person who got scammed this way, so be careful!

Florian did some gemological testings:
Image
All credits: Florian le Goff.

Image
These "Malaya garnets rough" turned out to be nanosital. Photo credit: Julien Sellier


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 Post subject: Re: Garnet simulant in Tanzania
PostPosted: Mon Oct 02, 2017 1:57 pm 
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Thank you!!

Think no problem in a cut stone but the rough....

Is it magnetic?

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 Post subject: Re: Garnet simulant in Tanzania
PostPosted: Mon Oct 02, 2017 11:32 pm 
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I don't know if it's magnetic Marlow, I can ask Florian.

The simulant was clearly "worked" in order to fool rough buyers, that's for sure.


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 Post subject: Re: Garnet simulant in Tanzania
PostPosted: Tue Oct 03, 2017 12:41 am 
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Did he spot it in the field, or was this figured out after purchasing? Impressive work--it's amazing how devious people in the trade can be when they put their minds to it.

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 Post subject: Re: Garnet simulant in Tanzania
PostPosted: Wed Oct 04, 2017 5:58 am 
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From what he wrote, he had strong a suspicion that something was wrong but he bought it to try and because it was fairly cheap.


Last edited by Dioptase on Thu Oct 05, 2017 7:12 am, edited 1 time in total.

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 Post subject: Re: Garnet simulant in Tanzania
PostPosted: Wed Oct 04, 2017 11:21 pm 
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Cool. I don't speak French unfortunately so I couldn't tell beyond the basic cognates.

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 Post subject: Re: Garnet simulant in Tanzania
PostPosted: Thu Oct 05, 2017 12:36 pm 
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For anyone unfamiliar with the term nanosital:
steinfroilein wrote:
Nanogem / Nanocrystal is suitable for faceting if you have experience with glass;
It is a glass-ceramic including Al2O3, MgO, TiO2, SiO2
Hardness 6,5-7
Density 3–3.3 gram/cm³
RI 1,61-1,65
Dispersion 0,012-0,02
Fire resitant max. 900 °C - stable in wax casting
Melting temperature 1500-1750°C
Crystallographic structure equal to that of Spinel
Homogeneous hue throughout each single stone in green, black, blue, gray blue, yellow, orange, peridot, garnet, purple to pink

See:
viewtopic.php?f=8&t=21422


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 Post subject: Re: Garnet simulant in Tanzania
PostPosted: Thu Oct 05, 2017 1:25 pm 
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Judging from the pic, they look rather convincing. A pretty good job, scam-wise.

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 Post subject: Re: Garnet simulant in Tanzania
PostPosted: Thu Oct 05, 2017 3:50 pm 
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Still, I am surprised by the specific gravity, which does not really match synthetic spinel.


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 Post subject: Re: Garnet simulant in Tanzania
PostPosted: Thu Oct 05, 2017 5:36 pm 
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When they say "crystallographic structure equal to that of spinel" I think they mean "is singly refractive" and are just saying it in a way that is wrong. Structurally my guess is that it's just glass given the somewhat vague and contradictory stuff they say about it.

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 Post subject: Re: Garnet simulant in Tanzania
PostPosted: Thu Oct 05, 2017 6:51 pm 
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Agreed ↑


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 Post subject: Re: Garnet simulant in Tanzania
PostPosted: Fri Oct 06, 2017 9:20 am 
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The RI given in the initial post immediately made me think of synthetic spinel.
But of course, glass is an option as well, even with this RI.


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 Post subject: Re: Garnet simulant in Tanzania
PostPosted: Mon Oct 09, 2017 1:24 pm 
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Lick it ??


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 Post subject: Re: Garnet simulant in Tanzania
PostPosted: Mon Oct 09, 2017 2:30 pm 
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Bill Hanneman wrote:
Lick it ??


:shock:

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