The Association of Gemmological Laboratories (AGL) in Japan currently specifies that a blue-togreen tourmaline showing the characteristic "neon" color due to copper can only be called "Paraiba" as a trade name on an identification report when the stone is confirmed to be from Brazil. AGL allows the "Paraiba" name to be used for tourmalines from Rio Grande do Norte (Mulungu and Alto dos Quintos), since separating them from Mina da Batalha stones is difficult, and material imported into Japan is a mixture of tourmalines from both states. This policy is consistent with that advocated by most gem dealers who are handling the Brazilian "Paraiba" tourmaline. However, as supported by the research reported in this article, Cu-bearing tourmalines from Brazil, Nigeria, and Mozambique are difficult to distinguish from one another by standard gemological testing methods. Therefore, AGL and the Laboratory Manual Harmonization Committee (LMHCJ decided to reconsider the nomenclature for "Paraiba" tourmaline. The LMHC consists of representatives from the AGTA-Gemological Testing Center (U.S.), CISG (Italy), GAAJ Laboratory (Japan), GIA Laboratory (U.S.), GIT-Gem Testing Laboratory (Thailand), Gubelin Gem Lab (Switzerland), and SSEF Swiss Gemmological Institute (Switzerland). At the LMHC's October 2005 meeting in Lucerne, and at the February 2006 Gemstone Industry & Laboratory Conference in Tucson, the LMHC group agreed to define "Paraiba" tourmaline as a blue ("neon" blue, or violet), bluish green to greenish blue, or green elbaite tourmaline containing Cu and Mn, similar to the material that was originally mined in Paraiba, Brazil; any "Paraiba" tourmaline, regardless of its geographic origin, shall be described with the following wording on a gem identification report:
This policy is consistent with current CIBJO practice, which defines "Paraiba" tourmaline as having a "green to blue color caused by copper," but no definition is made according to locality. Thus, CIBJO also considers "Paraiba" tourmaline to be a general variety or trade name.
At present, AGL will fall into step with the recommendation of the LMHC group, and will disclose a new nomenclature for "Paraiba" tourmaline later this year.
Since the initial discovery of magnificent brightly colored tourmaline at Mina da Batalha in Brazil's Paraiba State, Cu-bearing elbaite has also been mined from Brazil's Rio Grande do Norte State (Mulungu and Alto dos Quintos), as well as in Nigeria and Mozambique. Overlap in the gemological properties and chemical compositions of tourmaline from these localities makes it difficult to distinguish their geographic origins with the testing techniques available in most gemological laboratories.
The common presence of yellowish brown needle-like growth tubes in the Nigerian tourmalines is suggestive of their origin. Also, native copper was most commonly seen in the Nigerian and a few Brazilian tourmalines, but thus far it has not been documented in stones from Mozambique.
This study has shown that chemical fingerprinting by the LA-ICP-MS technique is useful for distinguishing Cu-bearing tourmaline from the various localities. Geochemical plots of CuO+MnO versus Ga+Pb, CuO+MnO versus PbjBe, and Mg-Zn-Pb reveal that quantitative data for these elements may permit a reliable distinction of Brazilian stones from their counterparts mined in Nigeria and Mozambique. The Nigerian tourmalines contained larger amounts of the trace elements Ga, Ge, and Pb, whereas Brazilian tourmalines were enriched in Mg, Zn, and Sb. The Mozambique samples showed high contents of Be, Sc, Ga, and Pb, and Bi, but a lack of Mg.
Although the major laboratories have agreed to use Paraiba tourmaline as a trade name for blue ("neon" blue, or violet), bluish green to greenish blue, or green Cu- and Mn-bearing elbaites, some labs may wish to provide the additional service of establishing the precise country of origin. On the basis of the research completed to date, such a distinction usually requires quantitative chemical analysis. As further discoveries are made in other parts of the world, additional research will be needed to reconfirm the criteria or establish new ones.
The above Conclusion is an excerpt from Gems and Gemology Magazine, Volume XLII, Spring 2006, entitle: "Paraiba"-Type Copper-Bearing Tourmaline from Brazil, Nigeria and Mozambique: Chemical Fingerprinting by LA-ICP-MS
"Paraiba" is being re-defined within the Gemstone
Trade. Learn More about what some labs are calling "Paraiba" Tourmaline:
Update on the Paraiba Tourmaline Origin (JCK Magazine 2006)