Bieberite - Encyclopedia

    Class : Sulphates, chromates, molybdates
    Subclass : Anhydrous sulphates
    Crystal System : Monoclinic
    Chemistry : CoSO4 7H2O
    Rarity : Very rare

Bieberite is an extremely rare hydrated cobalt sulphate, with the same crystalline structure as melanterite. It owes its name to its place of discovery : Bieber, Hesse, Germany. It forms red-pink or pale purple coatings and spherolites in the oxidation zone of cobalt deposits.

Main photo : Bieberite from Torgal Mine, Beja, Portugal © Pedro Alves

Bieberite in the World

It is a mineral known in less than twenty localities, the most classic specimens coming from the German veins of Bieber (Hesse) and Siegen (North Rhine).

Photo on the right : Biébérite from the Aure valley, Hautes-Pyrénées, France © Patrice Queneau

Bieberite in France

In France, bieberite is reported in the oxidation products of the cobalt-silver deposit at Chalanches near Allemont (Isère), but also at Finosa near Corte (Haute-Corse) and in the Aure valley (Hautes-Pyrénées).

Twinning and special crystallizations

No known twin known for this mineral species.

Fakes and treatments

No fake or treatment recorded for this mineral species.

Hardness : 2
Density : 1.96
Fracture : Irregular
Trace : White

TP : Translucent to opaque
RI : 1.477 to 1.489
Birefringence : 0,012
Optical character : Biaxial -
Pleochroism : None
Fluorescence : None

Solubility : Water

Magnetism : None
Radioactivity : None