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 Post subject: Diamond classification - the diamond types
PostPosted: Sat Jan 30, 2016 12:25 am 
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I just received a preview of this excellent article on the detection of diamond types using FTIR spectroscopy.
A must read!
Question Alberto and Mikko:
Once we identify the diamond type of an unknown using the FTIR can we also positively determine HPHT treatment or synthetic origin?
[pdfview]http://www.gemmoraman.com/Portals/0/Documents/DiamondType.pdf[/pdfview]


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 Post subject: Re: Diamond classification - the diamond types
PostPosted: Wed Feb 03, 2016 10:01 pm 
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Related earlier article here:
http://www.gia.edu/gems-gemology/spring ... ectroscopy
Diamond application notes for two commercial Fourier Transform Infrared spectroscopes:
https://www.bruker.com/fileadmin/user_u ... nds_EN.pdf
https://www.thermoscientific.com/conten ... 10278~.pdf

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 Post subject: Re: Diamond classification - the diamond types
PostPosted: Fri Feb 12, 2016 6:14 am 
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Barbra Voltaire wrote:
I just received a preview of this excellent article on the detection of diamond types using FTIR spectroscopy.
A must read!
Question Alberto and Mikko:
Once we identify the diamond type of an unknown using the FTIR can we also positively determine HPHT treatment or synthetic origin?
[pdfview]http://www.gemmoraman.com/Portals/0/Documents/DiamondType.pdf[/pdfview]


Thank you for the compliments, Barbra :D . and sorry for the very late reply :oops: we just get back from Tucson and just started dealing with all the work accumulated on the desk during our absence... :cry: .
about your question, there is not a simple and direct answer to that, unfortunately.
Knowing the exact diamond type is a huge step towards the identification of possible treated and synthetic stones and, of course FTIR is obviously THE tool. the spectrum can provide for additional information as an example, some minor boron presence in IIa as seen in fig 8 (vast majority of HPHT synthetics) and other specific peaks coming from defects typical of some CVD production but, in many cases, its a combination of multiple techniques that can solve the issue. Even PL alone in many cases is able to spot for the HPHT treatment as described in a previously released application note ( http://www.gemmoraman.com/Articles/HPHT.aspx ) but, there are limitations even here, in some HPHT treated the presence of PL features is missing even in liquid nitrogen immersion. That said, given that >95% of colorless to near colorless stones are high nitrogen type IaAB, those cannot be synthetic or HPHT-treated :wink: and, in the end, as for many other aspects of Gemology, the combination of multiple techniques is the only way to be relatively sure about what we are dealing with....

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 Post subject: Re: Diamond classification - the diamond types
PostPosted: Thu Mar 17, 2016 2:11 am 
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Really useful information though for the beginners.


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