DURANGITE

    Class : Phosphates, arsenates, vanadates
    Subclass : Anhydrous arsenates
    Crystal system : Monoclinic
    Chemistry : NaAl(AsO4)F
    Rarity : Very rare

Durangite is a very rare sodium and aluminum arsenate, whose genesis seems linked to pneumatolytic emanations. It is in fact known in veins cutting alkaline rhyolites with tridymite, in pegmatite dykes and high temperature veins with cassiterite and topaz. It owes its name to its discovery location : the Barranca tin mine in the state of Durango (Mexico). Durangite commonly forms automorphic crystals, up to 3 cm maximum, with rough faces, red-orange to dark red in color, sometimes yellow in various shades.

Main photo : Durangite from Thomas Range, Utah, USA © Dan Weinrich

Durangite from Barranca Mine Durango, Mexico © Rob Lavinsky
Durangite from Barranca Mine Durango, Mexico © Rob Lavinsky
Durangite from Thomas Range, Utah, USA © Chris Stefano
Durangite from Barranca Mine Durango, Mexico © Rob Lavinsky

Durangite in the World

Durangite is known in less than 5 localities in the world. Crystals of 1.5 cm are known from the Thomas Range Mountains (Utah), but the best crystals in the world were extracted from the Barranca tin mine in the state of Durango (Mexico) its type-locality where they can measure up to 3 cm. It is reported from New Ross (Canada), Jolotca (Romania) and a few sites in New Mexico (USA).

Durangite in France

Durangite is not present in the French underground.

Twinning

No twin known for this mineral species.

Fakes and treatments

No fake listed for this mineral species.


Hardness : 5.5
Density : 3.94 to 4.07
Fracture : Irregular
Streak : Yellow

TP : Translucent
RI : 1.634 to 1.685
Birefringence : 0.051
Optical character : Biaxial -
Pleochroism : Visible
Fluorescence : None

Solubility : Sulfuric acid


Magnetism : None
Radioactivity : None