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Say hello to the real Mozambique "Paraiba" Tourmaline!
Part II or our III Part series on the heavy metal bulk diffusion of gemstones!
Rather than provide you with a lot of rhetorical explanations this edition, I am instead going to simply let the images speak for themselves.
During the final days of our andesine investigations we were contacted by dealers in several countries that bulk diffusion was not exclusive to andesine. That, in fact, the process of heavy metal bulk diffusion of gemstones was being done on an array of gemstones with Mozambique “ Paraiba ” Tourmaline among its most famous. And various US Patents had even been granted regarding the bulk diffusion of heavy metals into gemstones, including US Patents # 6,635,309 and # 5,888,918 held by Richard D. Pollack, researched and reported to us by ISG Alumni John LeBourgeois, that may eventually allow us to duplicate the treatment.
 We began to accumulate as many study specimens as possible in order to have the greatest chance of finding the diagnostic features of this bulk diffusion of the Mozambique tourmaline. To date we have obtained over 200 specimens of tourmaline from Brazil and Mozambique for study at a cost of several thousand dollars to the ISG. But this is an important issue for consumer protection that we believe must be advanced.
We immediately began seeing some of the very same features with the tourmaline that we saw with andesine, as noted in the images at left and below. This included unusual red and yellow filled needles that deviated from the empty and iron filled needles normally seen in tourmaline as reported in the PHOTOATLAS of Inclusions in Gemstones, Volume 2 by Gubelin and Koivula, pp 775.
These features were very much like the diffused andesine features with the exception that they followed the hollow growth tubes shown by Koivula instead of the ribbon like lamella features of andesine. The key was to identify the material filling the tubes.
Unlike andesine, with the tourmaline we found rough specimens on the market. And all of the rough have two important features: (1) the outer surface of the stones have a coating and residual paste like substance that gives a Raman scan totally unlike tourmaline, and (2) once we took a Dremel and cut away some of the rough crystal, we got a clearly defined Raman scan of tourmaline as confirmed by our own database and the RRUFF online Raman database. Images are below of the rough surfaces and the Raman scans. The interior scan is a normal tourmaline scan.
There are two issues on the crusty red and yellow material on the surface: (1) it is fairly fragile. You can scrape it off with tweezers, and (2) it pervades deep into the tubes of the tourmaline. At many times it permeates the tubes completely from one end of the stone to the other. Below you will see some of the yellow filled features of these Mozambique tourmalines.
We were able to confirm through the Raman that the yellow filler material throughout the tourmaline needles was the same material crusted up on the exterior surface of the rough tourmaline. The yellow needle above and below was scanned with our Enwave Optronics Raman Microscope, and compared to the Raman scan of the yellow encrusted surface of the rough tourmaline. The composite of the Raman scans is shown below.
  And of course, we thought about the fact that this material might be polishing compound. Even though there was no reason for facet polishing compound to be crusted up on the surface of water worn pebbles of tourmaline. But just to be careful, we obtained specimens of faceting compound for Raman comparison to the red and yellow material on and in the Mozambique tourmaline. Here are the results below using tin oxide, cerium oxide, chrome oxide and others. The Linde A and B compounds were so much different that we did not include them. Obviously, none of these Raman scans duplicates our scans of the filler material.   (with appreciation to Barry Bridgestock and Larry Heath) Next, it was reported to us that a previous edition of GIA’s Gems and Gemology had identified some of the needles as being filled with hematite. And given the possibility of perhaps hematite, rutile needles, and copper (we are, after all, talking about the term “ Paraiba ” tourmaline) we gathered from our own ISG Student Reference Library Collection of gemstones, as well as the RRUFF files, and did our own comparison of Raman scans of these minerals to see if any matched. They did not, with the exception of the native copper that we will see below.  
Perhaps the most interesting revelation was with the red filled needles and tubes. Below left you see ISG Inventory #9668.1, a .66 carat Mozambique “Paraiba” Tourmaline sold to us by a dealer in Thailand . Below right you see the 120x magnified image of the red filled tubes as seen in the first image. Below…..the Raman scan of this filled tube. It appears to us that it virtually matches the Raman scan of our pure native copper.
So here is the question: In a Mozambique “ Paraiba ” Tourmaline that is reported by every reliable source in the world as having a “trace” of copper……how did this tourmaline get what appears to be multiple tubes filled with solid copper compound? And perhaps the most unusual tubes and needles we found are those that contain both the yellow and red material from the surface coating of the rough crystals.
 There is far more evidence and many more images than we were able to provide here in this newsletter. A group shot of about half of our study specimens is at left, and our research will continue. Of course, for many out there we have raised more questions than we have answered. What exactly is this material on, and in, these Mozambique “ Paraiba ” Tourmalines? And if the Mozambique material is indeed bulk diffused, should it be called “Paraiba ” at all?
For answers we are going to have to wait a few weeks. The ISG is forming a special committee of experts including some of the industry’s leading authorities on mineralogy and gemstone treatments. We have established a working relationship with two major industrial labs to perform advanced level testing of this material to find out exactly what is going on with these tourmalines. Due to the enormity of this situation, we feel that all due diligence is needed to end the debate on heavy metal bulk diffusion of gemstones, and the use of the term “Paraiba” on tourmalines enhanced by this method.
As soon as we have the final results, and these have been reviewed by our committee, we will publish these for you. Until then, we urge you to review the information in this edition and our previous edition on the issue of Mozambique “ Paraiba ” Tourmaline as we now move on to other topics of interest in the world of gemology.
Robert James FGA, GG
President, International School of Gemology
©2008 International School of Gemology . ALL RIGHTS RESERVED
All images are taken using the ISG Student Reference Collection of gemstones in the ISG office. We do urge and support sharing of this information in its entirety, with copyright notices intact, to others who are interested in the study of gemology. Jeweler’s Associations are welcome to distribute to your members.
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