Lab Alert: GIA Reports Pink Color Around Growth Tubes in Copper-Bearing Tourmalines

[diagem]

From GIA Insider..., January 28, Volume 11, Issue 2

"Jan. 28, 2009

Lab Alert:
GIA Reports Pink Color Around Growth Tubes in Copper-Bearing Tourmalines Results from Natural Irradiation

Samples of blue to blue-green, copper-bearing tourmaline containing surface-reaching growth tubes surrounded by intense pink "sleeves" have recently been seen in the trade. In response to rumors of possible diffusion treatment, GIA Laboratory staff members John I. Koivula, Kevin Nagle, Andy Shen and Philip Owens carefully examined several of these tourmalines over the past year. Based on this examination, the GIA team determined that the pink zones were produced by fluids containing naturally occurring radioactive material.

In all instances where pink coloration was observed, the growth features surrounded by the pink color reached the surface of the stones. In cases where growth tubes did not reach the surface, no pink color was seen. When these pink zones were viewed down their length, the color was observed to bleed out into the surrounding tourmaline host, becoming weaker until it gradually faded away. If post-growth matter in the tube created a blockage, coloration occurred only to that point. Additionally, any cracks extending from or between the growth tubes also showed a pink color.

Radiation is known to produce pink-to-red color in tourmaline. The coloration of surface-reaching features in tourmaline by invading radioactive fluids has not been reported in the literature; however, there have been reports of both smoky quartz and green diamonds with coloration that was caused by exposure to naturally occurring radioactive fluids. This mechanism explains all the observations of pink and red in these tourmalines.

"Since radiation is the cause of pink color in tourmaline, the presence of these features should not be attributed to any type of intentional diffusion, but rather to the influx of radioactive fluids in their post-growth environment," said GIA Laboratory Chief Gemologist John I. Koivula, one of the study''s authors.

All the copper-bearing tourmaline samples with this feature observed thus far have come from Mozambique. This suggests that this type of inclusion feature may be characteristic of that locality.

The presence of the pink zones in these otherwise blue to blue-green gems also provides proof that the host tourmalines were not heat treated, since the temperature needed to treat copper-bearing Mozambique material exceeds the published stable temperature for pink-to-red color in tourmaline.

An article by Koivula and his colleagues detailing these observations will appear in the Spring 2009 issue of GIA''s Gems & Gemology, due out in April. Subscribe online or call toll-free (800) 421-7250, ext. 7142. Outside the U.S. and Canada, call (760) 603-4000, ext. 7142."

 

[T L]

I definitely have stopped trusting material from Mozambique because of this. Thanks for posting this to the forum.

 

[karee888]

so....is it bad to own one, then? can it be harmful to a person?

 

[innerkitten]

edited.

 

[mercoledi]

Personally, I think that''s pretty darn cool. Yea science!

TL- Why do you avoid them? Because you don''t want pink in your green, or because they could theoretically still be hot?

 

[T L]

Date: 1/28/2009 6:08:05 PM
Author: mercoledi
Personally, I think that's pretty darn cool. Yea science!

TL- Why do you avoid them? Because you don't want pink in your green, or because they could theoretically still be hot?

I don't like treated stones, in particular nuked stones. I like stones that come out of the ground the color they are with as little human intervention as possible except for cutting. I used to buy heated tourmalines, but I don't anymore. The older I get, the more of a "purist" I've become. I'm not saying that treated stones are bad, and many people get a load of enjoyment from their treated stones, but treatments personally bother me.

The problem with this Mozambique material is that it's being sold all over ebay and by sellers that are told it wasn't treated, and the general public thinks they're buying untreated, or just heated material. There's still more research involved, but until we know the definitive facts about the treatments on this material, I am just going to stay away from it for now.

Treated and synthesized stones do allow people to have colors and stones they would not otherwise afford, and that's a good thing, but there's a very shady other side of the coin. Treatments and synthetics are becoming more and more prolific, and there is a great deal of deception involved with non-disclosure of these treatments and synthetics on ebay, and by regular sellers. Sometimes the sellers themselves are hoodwinked into believing the material they receive is not treated.

I can tell you that blue topaz gets it's color by irradiation, and it was radioactive to a degree, enough that the United States Nuclear Regulatory Commission had to get involved to enusre that the irradiated blue topaz being sold to the American public was safe. Regardless of whether it is safe or not, I just don't like stones irradiated by man. Green diamonds get their color from the earth's natural radiation, and that does not bother me.

 

[Harriet]

I'd like to know how much harm the radioactive liquid poses. If it's not much, the findings argue for the Mozambique material rather than against it. Afterall, they show that the gems are not even heated by man.

 

[mercoledi]

Date: 1/28/2009 6:28:33 PM
Author: tourmaline_lover

Date: 1/28/2009 6:08:05 PM

Author: mercoledi

Personally, I think that''s pretty darn cool. Yea science!


TL- Why do you avoid them? Because you don''t want pink in your green, or because they could theoretically still be hot?

I don''t like treated stones, in particular nuked stones. I like stones that come out of the ground the color they are with as little human intervention as possible except for cutting. I used to buy heated tourmalines, but I don''t anymore. The older I get, the more of a ''purist'' I''ve become. I''m not saying that treated stones are bad, and many people get a load of enjoyment from their treated stones, but treatments personally bother me.


The problem with this Mozambique material is that it''s being sold all over ebay and by sellers that are told it wasn''t treated, and the general public thinks they''re buying untreated, or just heated material. There''s still more research involved, but until we know the definitive facts about the treatments on this material, I am just going to stay away from it for now.


Treated and synthesized stones do allow people to have colors and stones they would not otherwise afford, and that''s a good thing, but there''s a very shady other side of the coin. Treatments and synthetics are becoming more and more prolific, and there is a great deal of deception involved with non-disclosure of these treatments and synthetics on ebay, and by regular sellers. Sometimes the sellers themselves are hoodwinked into believing the material they receive is not treated.


I can tell you that blue topaz gets it''s color by irradiation, and it was radioactive to a degree, enough that the United States Nuclear Regulatory Commission had to get involved to enusre that the irradiated blue topaz being sold to the American public was safe. Regardless of whether it is safe or not, I just don''t like stones irradiated by man. Green diamonds get their color from the earth''s natural radiation, and that does not bother me.

I can understand avoiding treated stones, but I took the report to mean that the color change was caused by irradiation after crystal formation but before mining, is that incorrect?

 

[T L]

The problem isn''t so much that it''s being irradiated or not, but the fact that this is not being disclosed to the buying public. This is similar to the Andesine case where everyone thought it was a natural color stone, and the lid was blown off of that when it was determined to be diffused.

 

[T L]

Date: 1/28/2009 6:40:17 PM
Author: mercoledi


I can understand avoiding treated stones, but I took the report to mean that the color change was caused by irradiation after crystal formation but before mining, is that incorrect?

It is not known for sure at this juncture. I do know for a fact that pink tourmaline is being irradiated, so I''m unsure of whether the intent of this article is to blow the lid off of that, or just to highlight natural radiation in tourmaline. There is talk of diffusion in Mozambique curprian tourmaline, and this particular article might be a response to that. Until we know more, I''m just being cautious, although there are gemologists that think this diffusion of copper bearing tourmaline is hogwash.

 

[colormyworld]

Date: 1/28/2009 6:46:04 PM
Author: tourmaline_lover

Date: 1/28/2009 6:40:17 PM
Author: mercoledi


I can understand avoiding treated stones, but I took the report to mean that the color change was caused by irradiation after crystal formation but before mining, is that incorrect?

It is not known for sure at this juncture. I do know for a fact that pink tourmaline is being irradiated, so I''m unsure of whether the intent of this article is to blow the lid off of that, or just to highlight natural radiation in tourmaline. There is talk of diffusion in Mozambique curprian tourmaline, and this particular article might be a response to that. Until we know more, I''m just being cautious, although there are gemologists that think this diffusion of copper bearing tourmaline is hogwash.

I have only heard of this difusion of tourmalines coming from one source. Seems as though this small but vocal group has gone diffusion loco in my opinion. They are saying not just andesines and tourmaline but certain types of garnets and other stones used for jewelery. While I think andesines may have been treated. IMO I have seen no good evidence from this group that makes sense to me. Take my statment with a grain of salt though as I am not an expert. If this group really wanted to go after those not disclosing treatments. Red and pink tourmaline would really be the place to start. As most end users have no knowledge of this treatment. Far worse is that the treatment is undetectible by the labs. .

 

[Harriet]

Date: 1/28/2009 6:46:04 PM
Author: tourmaline_lover
It is not known for sure at this juncture. I do know for a fact that pink tourmaline is being irradiated, so I''m unsure of whether the intent of this article is to blow the lid off of that, or just to highlight natural radiation in tourmaline. There is talk of diffusion in Mozambique curprian tourmaline, and this particular article might be a response to that. Until we know more, I''m just being cautious, although there are gemologists that think this diffusion of copper bearing tourmaline is hogwash.

Is that the case with every pink tourmaline? Would you mind citing your source?

 

[Harriet]

I still do not see how the article argues against Mozambique cuprian tourmalines.

 

[T L]

Date: 1/28/2009 7:55:01 PM
Author: Harriet

Date: 1/28/2009 6:46:04 PM
Author: tourmaline_lover
It is not known for sure at this juncture. I do know for a fact that pink tourmaline is being irradiated, so I'm unsure of whether the intent of this article is to blow the lid off of that, or just to highlight natural radiation in tourmaline. There is talk of diffusion in Mozambique curprian tourmaline, and this particular article might be a response to that. Until we know more, I'm just being cautious, although there are gemologists that think this diffusion of copper bearing tourmaline is hogwash.

Is that the case with every pink tourmaline? Would you mind citing your source?

It is another forum which I cannot mention here, but is full of gemologists and gem experts.

It is not the case with every pink tourmaline, but stones that come though Brazil and Thailand for faceting primarily. I was told that the rough is not irradiated, so if you get a stone from the same person who facets it, that is helpful, although not a guarantee.

 

[Harriet]

Oh dear. It''s a good thing I returned a pair of rubellites.

 

[colormyworld]

If it works for cut stones. What is to prevent the rough from also being treated in this manner?

 

[T L]

I don't know, but this document from faceters.com talks a bit more about it in the middle of the page. He states that the gems are first cut then irradiated. He also states that this treatment is widely done and often not disclosed.

http://www.faceters.com/how_to_buy/buy1.shtml

 

[coatimundi_org]

Date: 1/28/2009 7:28:15 PM
Author: colormyworld

I have only heard of this difusion of tourmalines coming from one source. Seems as though this small but vocal group has gone diffusion loco in my opinion. They are saying not just andesines and tourmaline but certain types of garnets and other stones used for jewelery. While I think andesines may have been treated. IMO I have seen no good evidence from this group that makes sense to me. Take my statment with a grain of salt though as I am not an expert. If this group really wanted to go after those not disclosing treatments. Red and pink tourmaline would really be the place to start. As most end users have no knowledge of this treatment. Far worse is that the treatment is undetectible by the labs. .

Makes sense CMW.

I read the article to refute the recent claims about the diffusion of copper bearing blue-green tourmaline from Mozambique. It also states that pink/red tourmaline is naturally irradiated.

It is impossible to tell if green diamonds of the more natural looking hues are irradiated by man or nature, I don't see how pink-red tourmaline would be an easier catch. Perhaps pink tourmaline will end up like synthetic amethyst--with the general public accepting or not really caring about the difference. Rubellite, of course, would be another story, because of value.

 

[Harriet]

Phew, Coats. I was beginning to doubt my reading comprehension.

 

[chrono]

Maybe it''s just me but my interpretation is that this makes it easier to determine if tourmalines are nuked/treated or not, in particular for Mozambique stones if one has a high powered loupe/microscope and is able to look for these tubes.

 

[Sagebrush]

All,

There is a lot of mis-information on the web about tourmaline treatments. Both pink and green are frequently treated by low-temperature heat. The green to drive off the yellow, the pink to deepen the color. This is normally done by cutters, not usually disclosed partially because it is undetectable. Pink tourmaline is sometimes irradiated. I am not sure if this treatment is detectable.

Recently, there have been unsupported charges floating around the internet that Mozambique cuprian tourmaline has been deep diffused with copper. I wrote a post on my blog GemWise: "Copper Diffusion in Tourmaline, Is This Gemology''s New Worst Nightmare". Long story short, I believe these charges to be baseless.

There are a lot of gems on Ebay called "Paraiba" Buyer beware!

The GIA report talks about natural radiation. Won''t make you sterile!

Best

 

[Harriet]

Richard,
Thanks for the clarification.
P.S. I''m glad there''s no need to carry a Geiger counter around.

 

[JaxBradGG]

Did anyone read this months copy Gems and Gemology??? It talks about the "Induced Copper Contamination of Tourmaline." Pretty interesting article about GIA''s testing of cuprian tourmaline and of tourmaline that was cut on a copper lap. page 367.

 

[coatimundi_org]

Date: 1/29/2009 10:13:13 AM
Author: JaxBradGG
Did anyone read this months copy Gems and Gemology??? It talks about the 'Induced Copper Contamination of Tourmaline.' Pretty interesting article about GIA's testing of cuprian tourmaline and of tourmaline that was cut on a copper lap. page 367.

Yup--they found that tourmaline with surface reaching fractures polished on a copper lap may accidentally be surface contaminated by copper.

They also discuss intentional contamination via concentrated copper salt solution. From what I understand, it is a surface contamination that can potentially be detected by energy dispersive x ray fluorescence--shows in the spectrum of individual stones. In the end, it states that GIA has a specific "cleaning protocol" to deal with surface contamination before testing, so a good lab should be able to detect contamination whether intentional or unintentional.

If I was buying true copper bearing blue-green tourmaline at true cu prices, I would surely get a lab report.

eta: side note about pink tourmaline--not surprised that some are irradiated, and it also doesn't bother me. The price of pink tourmaline is not high enough to warrant hullabulloo over treatment--just mho.

 

[Harriet]

Date: 1/29/2009 12:08:52 PM
Author: coatimundi
Yup--they found that tourmaline with surface reaching fractures polished on a copper lap may accidentally be surface contaminated by copper.
They also discuss intentional contamination via concentrated copper salt solution. From what I understand, it is a surface contamination that can potentially be detected by energy dispersive x ray fluorescence--shows in the spectrum of individual stones. In the end, it states that GIA has a specific ''cleaning protocol'' to deal with surface contamination before testing, so a good lab should be able to detect contamination whether intentional or unintentional.

If I was buying true copper bearing blue-green tourmaline at true cu prices, I would surely get a lab report.

eta: side note about pink tourmaline--not surprised that some are irradiated, and it also doesn''t bother me. The price of pink tourmaline is not high enough to warrant hullabulloo over treatment--just mho.

Unequivocally.

I share your humble opinion.