CIBJO releases Gemmological Special Report: considers process of separating measurable facts from opinion; See Gemological Articles below.
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 Post subject: SEM - Turquoise
PostPosted: Tue Jul 24, 2012 6:01 am 
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The Natural History Museum London tested some turquoise for me regards to treatment. They used a Scanning Electron Microscope.
They conclude they are turquoise, though one of the three pieces submited contained some chromium which they say may be indicative of
some kind of treatment, as this is not a element found in turquoise.
The nhm have sent me copies of the analysis. I have a problem understanding them :oops: :roll: , and the person i was dealing with as since left the nhm. I would appreciate any information on SEM and its use
to detect treatment on turquoise

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 Post subject: Re: SEM - Turquoise
PostPosted: Tue Jul 24, 2012 11:53 am 
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Joined: Sun Oct 16, 2005 12:22 pm
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What was your inspiration to send the specimen to The Natural History Museum?
Do they have a database for treated material?
Perhaps you would get more definitive answers sending an unknown to AGL....just a thought.


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 Post subject: Re: SEM - Turquoise
PostPosted: Mon Jul 30, 2012 7:55 am 
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Barbra turquoise is one of my favorite stones, though i do not like treated stones. doubt that the nhm would have a database for treated material. I bought this turquoise in Jaipur, the Jaipur dealers get it from Mainland China. Trying to find out if they add anything more to it than just a polymer. It is interesting that one stone contained some chromium that may indicative of some kind of treatment
Next time I am in Jaipur , i will take this up with the Gem testing Lab , as most of the turquoise in Jaipur is now coming from mainland China

I am writing a artical on Turquoise, just put some pictures up on my
amber website, click on amber next to samples menu. it goes to it

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