Asbolane - Encyclopedia

    Class : Oxides and hydroxides
    Subclass : Hydroxides and hydrates
    Crystal System : Rhombohedral
    Chemistry : (Co,Ni)xMn(O,OH)4 nH2O
    Rarity : Rare

Asbolane is a rare mineral from the psilomelane group. It is the "cobaltiferous psilomelane", present in the superficial parts of cobalt and manganese concentrations. It is surely a more common mineral than you think, but its determination is not easy with simple means. It takes its name from the Greek asbole (soot) because of its appearance. It occurs in lamellar aggregates and masses of black hue with a matte luster. The crystals are micron in size. Asbolane was anecdotally exploited for cobalt in the lateritic nickel deposits of New Caledonia.

Main photo : Asbolane de Tiébaghi Mine, New Caledonia, France © Lilian Alizert

Asbolane in the World

The deposits of Schneeberg (Saxony, Germany) and Nijni Taguil (Urals), as well as the cobalt deposit of Bou Azzer (Morocco), yielded some of the most spectacular samples of this mineral. 

Asbolane in France

In France, asbolane is known in the superficial oxidized parts of the cobalt and silver vein of Chalanches (Isère), as well as in the lateritic nickel deposits of New Caledonia.

Twinning and special crystallizations

No twin known for this mineral species.

Fakes and treatments

No fake or treatment identified for this mineral species.

Hardness : 6
Density : 8.96
Fracture : Irregular
Trace : Brown to black

TP : Opaque
RI : -
Birefringence : -
Optical character : -
Pleochroism : None
Fluorescence : None

Solubility : None

Magnetism : None
Radioactivity : None