January 24 Through February 4—TUCSON, ARIZONA: Annual show
Welcome to the GemologyOnline.com Forum
A non-profit Forum for the exchange of gemological ideas
It is currently Tue Mar 19, 2024 2:45 am

All times are UTC - 4 hours




Post new topic Reply to topic  [ 7 posts ] 
Author Message
 Post subject: A blue diamond
PostPosted: Tue Oct 18, 2016 3:45 am 
Offline
New to the Forum or The Quiet Type

Joined: Mon Jun 13, 2016 2:04 am
Posts: 2
The stone I tested was Type IIb diamond, its boron peaks were positions at 1290, 2456, 2802, 2930, 4090cm-1, DiamondView test showed mosaic pattern which was typical natural Type II diamond’s characteristic. The one didn’t show any phosphorescence. One thing confused me was about the PL test (under LN), it revealed small peak at 741nm which could produce by natural and artificial irradiation. I have experienced some blue diamonds certified by GIA, small peak at PL 741nm were also found.

What do you command about this one?


Top
 Profile  
Reply with quote  
 Post subject: Re: A blue diamond
PostPosted: Tue Oct 18, 2016 11:38 am 
Offline
Site Admin
User avatar

Joined: Sun Oct 16, 2005 12:22 pm
Posts: 21600
Location: San Francisco
Bruce I moved your diamond topic to the appropriate place for diamond related topics.


Top
 Profile  
Reply with quote  
 Post subject: Re: A blue diamond
PostPosted: Mon Oct 24, 2016 9:36 am 
Offline
Site Admin
User avatar

Joined: Fri Apr 17, 2009 3:53 pm
Posts: 2049
Location: Sweden
I have learned it is not uncommon to treat natural brownish type IIb to make them nice blue. Any signs of HPHT treatment in the PL spectrum? I would have it FTIR tested. Images of PL spectrum and the stone?

_________________
_____________
Conny Forsberg


Top
 Profile  
Reply with quote  
 Post subject: Re: A blue diamond
PostPosted: Thu Oct 27, 2016 3:10 am 
Offline
New to the Forum or The Quiet Type

Joined: Mon Jun 13, 2016 2:04 am
Posts: 2
This blue diamond was confirmed natural diamond already, not synthetic either CVD or HPHT.
Just doubted about the PL 741nm, a small peak was shown, could it be radiated or natural blue color?


Top
 Profile  
Reply with quote  
 Post subject: Re: A blue diamond
PostPosted: Thu Oct 27, 2016 11:25 pm 
Offline
Valued Contributor

Joined: Wed Oct 22, 2008 5:00 am
Posts: 344
Location: Finland
Many natural type IIb stones exhibit a small GR1-peak at 741nm, so no worry.
The name of the band is "general radiation", but irradiation is not the only cause for it. In case of natural IIa & IIb the reason is plastic deformation.
This peak is destroyed in HPHT-treatment, so I expect to see it in natural untreated type IIb stone. However, it is technically possible to post-irradiate the stone with minor dose for recreating the peak. I have only seen this done for IIa, but see no reason why it wouldn't work for IIb as well.

_________________
GemmoRaman GemmoFtir GemmoSphere


Top
 Profile  
Reply with quote  
 Post subject: Re: A blue diamond
PostPosted: Sat Oct 29, 2016 5:06 pm 
Offline
Moderator: Lapidary Diamonds
User avatar

Joined: Mon Aug 20, 2012 11:32 pm
Posts: 1747
Location: Florida, United States
Conny Forsberg wrote:
I have learned it is not uncommon to treat natural brownish type IIb to make them nice blue. Any signs of HPHT treatment in the PL spectrum? I would have it FTIR tested. Images of PL spectrum and the stone?


I have never seen a type 2b diamond exhibit a brown color. Perhaps you are thinking of type 2a?

_________________
http://adamasfacet.com


Top
 Profile  
Reply with quote  
 Post subject: Re: A blue diamond
PostPosted: Sun Oct 30, 2016 4:03 am 
Offline
Site Admin
User avatar

Joined: Fri Apr 17, 2009 3:53 pm
Posts: 2049
Location: Sweden
Should be brown-ish. As Brown tone in the blue. Call it off blue If you like.

_________________
_____________
Conny Forsberg


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 posts ] 

All times are UTC - 4 hours


Who is online

Users browsing this forum: No registered users and 5 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
Gemology Style ported to phpBB3 by Christian Bullock