MOUNANAITE
Class : Phosphates, arsenates, vanadates
Subclass : Anhydrous vanadates
Crystal system : Monoclinic
Chemistry : PbFe2(VO4)2(OH)2
Rarity : Very rare
Mounanaite is an iron and lead vanadate discovered in the surface oxidation zone of the Mounana uranium deposit (Gabon) from which it takes its name. Mounanaite forms tiny elongated pseudohexagonal or diamond-shaped crystals of a reddish-brown hue of sub-millimeter size, agglomerated in encrustations. It is associated with goethite and other vanadates, notably uranium (francevillite and curienite).
Main photo : Mounanaite from Mounana Mine, Gabon © Stephan Wolfsried
Mounanaite in the World
Twinning
Twins are common by rotation around [001] or on {1-11}.
Fakes and treatments
No fakes recorded for this mineral species.
Hardness : 4.5
Density : 4.85
Fracture : Undetermined
Streak : Undetermined
TP : Translucent to transparent
RI : -
Birefringence : -
Optical character : Biaxial
Pleochroism : Strong
Fluorescence : None
Solubility : -
Magnetism : NoneRadioactivity : None