SABUGALITE

    Class : Phosphates, arsenates, vanadates
    Subclass : Uranyl phosphates
    Crystal system : Monoclinic
    Chemistry : HAl(UO2)4(PO4)4 16H2O
    Rarity : Fairly common

Sabugalite is an hydrated uranium phosphate belonging to the autunite group. It is rarer than the latter but is frequently found associated with it in the oxidation zones of uranium deposits. It then forms thick incrustations on the periphery of the autunite. Its name comes from its discovery location : Sabugal (Portugal). Sabugalite forms elongated lamellar crystals in the shape of laths with fibrillar ends, often gathered in sheaves or lattices. They hardly reach a centimeter. Its color is straw yellow to lemon yellow and it fluoresces green under UV. It has locally constituted a uranium ore.

Main photo : Sabugalite from Entraygues-sur-Truyère, Aveyron, France © Christophe Boutry

Sabugalite in the World

Sabugalite is quite abundant in its type locality of Sabugal (Portugal). It is also present in the American deposits of Colorado (Marshall Pass, Cameron, Black Mesa), Utah and Wyoming. It is also known in the vanadium and uranium mines of Ciudad Rodrigo and Pedro Alvaro in the province of Salamanca (Spain).

Sabugalite in France

The most beautiful known crystals of sabugalite are French and come from the pitchblende veins of Limousin, notably Margnac, Compreignac and Pény (Haute-Vienne). It is also reported at the Bel Air mine (Deux-Sèvres), at the Prévinquières mine and at Entraygues-sur-Truyère (Aveyron) and at Pontivy (Morbihan).

Right photo : Sabugalite on phosphuranylite from Margnac, Haute-Vienne, France © Frédéric Delporte

Twinning

No twinning known for this mineral species.

Fakes and treatments

No fakes listed for this mineral species.


Hardness : 2.5
Density : 3.2
Fracture : Micaceous
Streak : Undetermined

TP : Translucent to transparent
RI : 1.564 to 1.584
Birefringence : 0.018 to 0.019
Optical character : Biaxial -
Pleochroism : Visible
Fluorescence : Yellowish green

Solubility : -

Magnetism : NoneRadioactivity : Very strong