Barbosalite - Encyclopedia

    Class : Phosphates, arsenates, vanadates
    Subclass : Anhydrous phosphates
    Crystal System : Monoclinic
    Chemistry : Fe3(PO4)2(OH)2
    Rarity : Rare

Barbosalite is a secondary phosphate formed by hydration and oxidation of primary phosphates (mainly triphylite) in complex granitic pegmatites. It owes its name to the Brazilian mineralogy professor Aliuzio Licinio de Mirande Barbosa of the School of Mines of Ouro Preto. Its crystals are squat prisms up to very small cuboids (0.25 mm). Most often this mineral forms powdery coatings and encrustations of microcrystals. Its color is very dark blue to black.

Main photo : Barbosalite from the Sandamap pegmatite, Daures Constituency, Erongo, Namibia © Stephan Wolfsried

Barbosalite from Criminoso, Agua Boa, Brazil © Van King
Barbosalite from Serra Branca pegmatite, Paraiba, Brazil © Stephan Wolfsried
Barbosalite from Jocão claim, Conselheiro Pena, Minas Gerais, Brazil © Stephan Wolfsried
Barbosalite from the Sandamap pegmatite, Erongo, Namibia © Stephan Wolfsried

Barbosalite in the World

The pegmatite from the Criminoso mine, near Agua Boa (Brazil) yielded beautiful crystals. The best occurrence in the world, however, remains the pegmatite of Bull Moose (South Dakota) from which masses of barbosalite exceeding 100 kg have been extracted, concealing small geodes lined with crystals of this mineral, and large crystals of strengite and metastrengite. Barbosalite is also known in the pegmatite of Sapucaia (Minas Gerais, Brazil), and in several other pegmatites of Portugal, the United States, Australia and Rwanda.

Barbosalite in France

In France, barbosalite has been described in Bessines-sur-Gartempe (Haute-Vienne).

Twinning and special crystallizations

The contact twins are described following (001) as a composition plan.

Fakes and treatments

No fake or treatment identified for this mineral species.

Hardness : 5.5 to 6
Density : 3.6
Fracture : Conchoidal
Trace : Blue to dark green

TP : Opaque to translucent
RI : 1.760 to 1.840
Birefringence : 0.075
Optical character : Biaxial +
Pleochroism : Visible
Fluorescence : None

Solubility : Hydrochloric acid

Magnetism : None
Radioactivity : None