Paraiba Tourmaline

Generic Information:

Name Origin: It is considered an unusual stone for its beauty and colors like a vivid blue and green that have never been seen before in other Tourmalines. The neon blue glow is distinctive, presenting a powerful beauty. It receives the name of Paraíba because the first stones with these characteristics were discovered in the Paraiba State located in Northeastern Brazil. It is one of the most valuable gemstones in the world due to its rarity and unique beauty.

Main Colors: Intense blue to violet-blue, greenish-blue, bluish-green, green. Vivid colors are termed by the market as neon, fluorescent or electric.

Producing Countries: Tourmaline deposits are found in pegmatites and alluvial deposits. The most important historical supplier is Brazil, in Paraíba and Rio Grande do Norte States. In 1988, a brilliant variety of Elbaite Tourmaline was discovered in Paraíba, Brazil. The colors of the Tourmalines were of a vivid intensity that swept the world of gems. The cause of its bright colors was the presence of copper, manganese, and, in some cases, traces of bismuth. After the discovery, other brightly colored Tourmalines were also discovered in Parelhas, in the State of Rio Grande do Norte, Brazil. These Tourmalines were also considered “Paraíba”. A few years later, in 2001, Tourmalines also containing copper were discovered in Nigeria and, later, in Mozambique. These stones also contained traces of magnesium and lead in smaller percentages than those in Brazil and, although they were not as intense as the Brazilian stones, they were officially designated as Paraiba Tourmaline by the International Conference of Gemstone Industry Laboratories. The largest productions in recent years have been in the Maraca and Mavuco mines, located in Nampula, Mozambique. Also, the Parelhas Mine in Rio Grande do Norte, Brazil, has regular production of small stones.

Common Shapes: Any shape is good for Paraiba Tourmaline, as its optical axis is lighter than in other tourmalines. As this gem often contains inclusions, it is important, during the sawing phase, to place the table so that needles and cracks are in a vertical position. Drops and ovals are the preferred shapes, as are round ones for stones under 4mm. Due to the common presence of inclusions, cabuchons are also cut with certain frequency.

Usual Treatment: Heat treatment between 400 and 560°C is used to open the color of darker blue crystals, as well as change the color of purple or lavender-colored materials to blue. In some stones with a greater presence of inclusions, such as in cabochons, treatment with colorless oil or resin can be done.

Gemological Data:

SPECIES:Paraiba Tourmaline
Hardness of Mohs: 7/7,5
Specific Density: 3,06 (+0,15 / -0,05)
Cleavage: None.
Fracture: Uneven, brittle conical
Crystal System: Hexagonal (trigonal) usually elongated crystals with triangular sections and rounded faces, clear striations parallel to the main axis; often, several prisms grow together.
Chemical Composition: (NaLiCa)(Fe₁₁MgMnAl)₃Al₆[(OH)₄(BO₃)₃Si₆O₁₈)]Aluminum complex borosilicate of variable composition.
Transparency: Transparent
Refractive Index: 1,624-1,644
Birefringence: 0.020
Dispersion: 0,017
Pleochroism: Strong green; dark green and light green. dark blue; dark blue and light blue.
Luster: Vitreous
Fluorescence: Weak or none