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 Thu Mar 28, 2024 8:47 pm

All times are UTC - 4 hours




Post new topic Reply to topic  [ 14 posts ] 
Author Message
 Post subject: Update on GIA's Heating of Mozambique Tourmaline
PostPosted: Sun Aug 02, 2009 1:00 am 
Offline
Active Member
User avatar

Joined: Thu Nov 17, 2005 10:27 pm
Posts: 91
Location: Bangkok
The following is ongoing research. Additional specimens are under study and will be reported on in future updates.

Diffusion of tourmaline experiment

The GIA's Bangkok Research Lab has updated their research on the heating of Mozambique tourmaline, finding that simple heating to 700°C with no additives changes yellow staining in fissures to a red color. The changes are often quite dramatic. In some cases, fissures, fractures, growth tubes and other surface-reaching openings showed no discernible yellow staining prior to heating, but after heating still turned red to purple. It is possible that these fissures contained natural contaminants, but not in great enough concentration to be easily visible prior to heating. It is also possible that the heating mobilizes the contaminants. In any event, this type of heating actually disfigures the stones, producing and enlarging fractures and making the stones uglier in overall color.

The causes of these heat-produced stains is still under investigation, but is thought to involve the conversion of limonite to hematite. That they have been found in stones that were not previously heat treated suggests that they are the result of contaminants that entered the gem naturally and were altered after the gems were heated.

In some cases, staining from the openings appeared to bleed into the body of the gem, but it is still uncertain if this is a result of an optical illusion resulting from blurring of focal points above and below the fissures or if it represents actually bleeding of color into the body of the stone.

This phenomena appears to be separate from the pink coloration that appears to be associated with natural radiation staining from what is believed to be invasion of uranium and thorium-bearing impurities while the crystals were in the ground. This is also discussed in the same paper.

Their conclusion regarding the latter is as follows:

"Clearly more specimens need to be analyzed before a better understanding of the mechanisms involved is achieved, however is would appear that an alternative and more likely cause for these color concentrations in tourmaline has now been firmly established. Certainly the assumption that these color concentrations are produced artificially by one of the diffusion processes has been put to question and been found to be lacking in substance."

Heating was performed by John Emmett (and possibly Troy Douthit), with the analytical research/testing done by the GIA Research Lab in Bangkok, under the direction of Ken Scarratt and Sudarat Saeseaw. Specimens were provided by NCS Group (the company I work for in Thailand), along with Miranda Gems of Hong Kong, which is the biggest miner of Mozambique paraíba tourmaline.

Note to all: This version of the GIA's ongoing research was uploaded to their website on July 28, 2009. See also this article from GIT, which was posted in July 2009, prior to the GIA update:

GIT article

Postscript: Although the GIA paper doesn't specifically mention it, there was no evidence that the stones tested were either synthetic tourmaline or diffusion-treated tsavorite masquerading as synthetic tourmaline. There is also no evidence that buying tourmalines from Thailand will foster hair growth on the palms, but this question probably deserves further study. Or perhaps just a show of hands would do.

_________________
Richard W. Hughes
"The price of wisdom is beyond rubies"
ruby-sapphire.com
lotusgemology.com


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Sun Aug 02, 2009 7:42 am 
Offline
Moderator
User avatar

Joined: Thu Dec 13, 2007 3:42 pm
Posts: 4091
Location: the Netherlands
Quote:
There is also no evidence that buying tourmalines from Thailand will foster hair growth on the palms


:D Sure?

cheers for the update Richard.


Top
 Profile  
Reply with quote  
 Post subject: Re: Update on GIA's Heating of Mozambique Tourmaline
PostPosted: Sun Aug 02, 2009 11:03 am 
Offline
Valued Contributor

Joined: Sun Mar 08, 2009 2:16 pm
Posts: 331
Richard Hughes wrote:


Postscript: Although the GIA paper doesn't specifically mention it, there was no evidence that the stones tested were either synthetic tourmaline or diffusion-treated tsavorite masquerading as synthetic tourmaline. There is also no evidence that buying tourmalines from Thailand will foster hair growth on the palms, but this question probably deserves further study. Or perhaps just a show of hands would do.


So here I am in this cyber coffee shop in town and I read Dick's postscript. :smt005 :smt005 .... several people were startled by my outburst. Thanks for this update and the good laugh. :lol:

Cheers, Bear


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Sun Aug 02, 2009 11:05 am 
Offline
Site Admin
User avatar

Joined: Fri May 12, 2006 11:24 am
Posts: 7523
Location: Rome, Italy
Thank you Richard....THANK YOU very MUCH!! :D :wink:
ciao
alberto

_________________
GemmoRaman-532 - GemmoFTIR - GemmoSphere - EXA


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Sun Aug 02, 2009 11:26 am 
Offline
Gemology Online Veteran

Joined: Mon Dec 01, 2008 6:43 pm
Posts: 615
Location: St. Paul, Minnesota
Really good information - thanks!


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Sun Aug 02, 2009 12:29 pm 
Offline
Platinum Member
User avatar

Joined: Fri Feb 24, 2006 1:20 am
Posts: 2756
Location: Southern California, U.S.A.
Come on -- I want to see a show of hands :smt006

Both of them, please!

_________________
Rick Martin

www.artcutgems.com


Top
 Profile  
Reply with quote  
 Post subject: Hands?
PostPosted: Sun Aug 02, 2009 1:15 pm 
Offline
Gemology Online Veteran

Joined: Thu Sep 25, 2008 10:33 am
Posts: 840
Location: Mars PA
Its too hairy for me to show, but I will try and clap for continuing to get the research done to limit the damage done by irresponcible accursations concerning Mozambique tourmaline.

I hope that some positive comes out of this research in the area of a definitive set of observations that can say whether a Mozambique tourmaline has been heated or not by man.

Bruce


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Sun Aug 02, 2009 1:35 pm 
Offline
Gemology Online Veteran
User avatar

Joined: Fri Oct 21, 2005 12:33 pm
Posts: 708
Location: Gemologist/dealer & author
Dick,

Well are we really surprised? Weren't we all aware that the "crud in the tubes" is and was a last ditch effort on the part of Messieurs James and Federman to save the crumbling edifice built of absurd claims, silly salvos and hackneyed hyperbole.

Well the science has spoken, and as I suggested before, Mr. James should have quit with andesine, by the time the dust cleared and the real science came out, few would have noticed that his methodology and conclusions just didn't hold up.

Hubris and tabloid journalism make for a potent combination and a heady brew, but eventually the truth has a way of getting out.

_________________
Author: Secrets Of The Gem Trade, The Connoisseur's Guide (2nd Edition) http://www.secretsofthegemtrade.com and The French Blue: http://www.thefrenchblue.com[/url]:


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Sun Aug 02, 2009 2:14 pm 
Offline
Valued Contributor

Joined: Tue Feb 19, 2008 11:49 am
Posts: 114
My Oh My! So what say the Cool-Aid Drinkers Now?


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Sun Aug 02, 2009 3:16 pm 
Offline
Site Admin

Joined: Thu Jan 05, 2006 4:27 pm
Posts: 1750
Excellent report...Thanks Richard It's nice to see there is a simple explanation that doesn't invoke the diffusion devil (he gets enough press as it is)


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Sun Aug 02, 2009 4:48 pm 
Offline
Gemology Online Veteran

Joined: Mon Dec 01, 2008 6:43 pm
Posts: 615
Location: St. Paul, Minnesota
stonecrazy wrote:
My Oh My! So what say the Cool-Aid Drinkers Now?


They will still come up with a variety of half-baked reasons why this proves NOTHING!!


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Sun Aug 02, 2009 4:51 pm 
Offline
Gemology Online Übergoddess

Joined: Tue Nov 06, 2007 3:16 am
Posts: 3170
:D thanks for the research conclusions and we look forward to the upcoming updates!!


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Mon Aug 03, 2009 3:09 pm 
Offline
Gemology Online Übergod
User avatar

Joined: Mon Oct 17, 2005 2:39 pm
Posts: 3528
Location: San Francisco Bay Area, CA
anitame wrote:
stonecrazy wrote:
My Oh My! So what say the Cool-Aid Drinkers Now?


They will still come up with a variety of half-baked reasons why this proves NOTHING!!


How about we focus on the above research/conclusions and avoid speculation on what third parties think/feel about it?


Top
 Profile  
Reply with quote  
 Post subject:
PostPosted: Mon Aug 03, 2009 11:55 pm 
Offline
Gold Member
User avatar

Joined: Fri Oct 12, 2007 10:22 pm
Posts: 1117
Location: Virginia
This was a terrific report! I learned a lot (alot?) just about natural processes.

Thanks for posting this.

_________________
Soil is not dirt.
http://hmmdesign.net


Top
 Profile  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 14 posts ] 

All times are UTC - 4 hours


Who is online

Users browsing this forum: No registered users and 8 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