Faceted brazilianite, 12.2 cts, 1.9 x 1.0 x 0.7 cm, Corrego Frio mine (type locality), Linopolis, Divino das Laranjeiras, Doce valley, Minas Gerais, Brazil. © Rob Lavinsky, www.iRocks.com. Used with permission.
Brazilianite’s lovely green to yellow colors make it a must for gem collectors. Large faceted stones are often flawed, but smaller cut gems can make beautiful jewelry pieces.
The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
| Data | Value |
|---|---|
| Name | Brazilianite |
| Crystallography | Monoclinic. Crystals equant, prismatic, spear-shaped; also striated. |
| Refractive Index | 1.602-1.623 |
| Colors | Colorless, pale yellow, yellowish green, greenish. |
| Luster | Vitreous. |
| Hardness | 5.5 |
| Fracture | Conchoidal |
| Specific Gravity | 2.980-2.995 |
| Birefringence | 0.019-0.021 |
| Cleavage | Good 1 direction |
| Dispersion | 0.014 |
| Heat Sensitivity | Yes |
| Luminescence | None |
| Luminescence Present | No |
| Transparency | Translucent to transparent. |
| Absorption Spectrum | Not diagnostic. |
| Formula | NaAl3(PO4)2(OH)4 |
| Pleochroism | Weak, merely a change in shade of color. |
| Optics | α = 1.602; β = 1.609; γ = 1.621-1.623. Biaxial (+), 2V = 71°. |
| Optic Sign | Biaxial + |
| Etymology | After Brazil, where the gem was first discovered. |
| Occurrence | Hydrothermal mineral in pegmatitic cavities. |
Brazilianites on matrix, 10.0 x 7.5 x 7.2 cm, Telirio Mine, Linopolis, Minas Gerais, Brazil. © Rob Lavinsky, www.iRocks.com. Used with permission.
Discovered in Brazil in 1944, large uncut brazilianite stones reside in many museums. Pieces such as these could yield large gems, but clean faceted gems over 15 carats are a great rarity. They also make stunning crystal specimens.
Yellowish green brazilianite, 2.23 cts, 8.7 x 6.8 x 5.4 mm, cushion cut, Brazil. © ARK Rare Gems. Used with permission.
Brazil, notably Conselheira Pena, Minas Gerais, remains the principal source of gem quality material in crystals up to large sizes. The Palermo Mine in Grafton, New Hampshire and sites in Yukon, Canada also yield fine but smaller specimens.
Brazilianites, Rapid Creek, Yukon, Canada. © Rob Lavinsky, www.iRocks.com. Used with permission.
Crystals from Brazil range in size up to 12 x 8 cm. Although some large gems have been cut, most gems range from 1-10 carats, or even smaller. Cut stones over 5 carats are scarce today.
Some of the sharp, yellow brazilianites inside this quartz vug reach 1.1 cm. That’s very large for this locality. The specimen measures 10.8 x 10.3 x 8.9 cm. Palermo Mine, North Groton, New Hampshire, USA. © Rob Lavinsky, www.iRocks.com. Used with permission.
Cut brazilianites, 0.78 and 2.00 cts. Photo © Joel E. Arem, PhD, FGA. Used with permission.
Heating brazilianite gems up to 140º C/284º F can lead to color loss. Heating up to 300º C/572º F will turn them colorless. A jeweler’s torch will easily reach these temperatures, so be wary if you’re taking a jewelry piece for repairs. Although brazilianites have a moderate hardness, they also have good cleavage and a tendency to fracture. Thus, protective settings and occasional wear are good ideas. Avoid mechanical cleaning such as steam or ultrasonic processes. Instead, use a soft brush, mild detergent, and warm water for cleaning. Consult our gemstone jewelry cleaning guide for more recommendations.
Brazilianite: Brazil, (3.0, 2.7). Photo © Joel E. Arem, PhD, FGA. Used with permission.
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