Roselite - Encyclopedia

    Class : Phosphates, arsenates, vanadates
    Subclass : Hydrated arsenates
    Crystal system : Monoclinic
    Chemistry : Ca2(Co,Mg)(AsO4)2 2H2O
    Rarity : Very rare

Roselite (sometimes called alpha-roselite to distinguish it from its triclinic dimorph, beta-roselite) is a rare cobalt arsenate from the oxidation zone of cobalt arsenide deposits. It owes its name to the mineralogist Gustave Rose of the University of Berlin. It occurs in small elongated prismatic crystals, pink to purple and purplish red, frequently grouped in spherolitic aggregates. It is a rare mineral coveted by collectors because of its attractive color.

Rosélite de Bou Azzer, Maroc
Roselite from Bou Azzer, Morocco
Roselite from Bou Azzer, Morocco
Roselite from Bou Azzer, Morocco
Roselite from Bou Azzer, Morocco

Roselite in the World

The best specimens of roselite come from the Arhbar mine in Bou Azzer (Morocco), where groups of brilliant crystals up to one centimeter, implanted on dolomite, have been discovered ; the association with pink scalenohedra of cobaltiferous calcite composes particularly aesthetic bouquets. Small purplish pink crystals on quartz were once extracted from the German mines of Schneeberg in Saxony (Daniel, Rappold), sites of discovery of the mineral. Roselite is also reported in two towns in Andalusia (Spain).

Roselite in France

This mineral is not present in the French underground.


Very common twin on {100}.

Fakes and treatments

No fake recorded for this mineral species.

Hardness : 3.5
Density : 3.46 to 3.74
Fracture : Undetermined
Trace : White to pink

TP : Translucent to transparent
RI : 1.694 to 1.735
Birefringence : 0.018
Optical character : Biaxial -
Pleochroism : Low
Fluorescence : None

Solubility : Acids

Magnetism : None
Radioactivity : None