Ianthinite - Encyclopedia
Class : Oxides and hydroxides
Subclass : Uranyl hydroxides
Crystal system : Orthorhombic
Chemistry : UO2 5UO3 10H2O
Rarity : Rare
Ianthinite is a rare mineral. It is the only hydrated supergene uranium mineral containing U4+ ion and one of the first pitchblende oxidation minerals. It is found in pitchblende cracks at the limit of the oxidation zone and the primary ore. Unstable, it hydrates very easily in the air and slowly transforms into schoepite. Its name comes from the Greek ianthinos (purple) in reference to its color. Ianthinite forms flattened acicular crystals, purple to reddish brown, of 2 mm at most, commonly grouped in sea urchins, rosettes or felts.
Main photo : Ianthinite partially altered to schoepite from the Clara Mine, Germany © Michael Förch
Ianthinite in the World
Twinning
No twins known for this mineral species.
Fakes and treatments
No fakes recorded for this mineral species.
Hardness : 2 to 3
Density : 5.16
Fracture : Irregular
Streak : Brown, purple
TP : Translucent to transparent
RI : 1.674 to 1.920
Birefringence : 0.246
Optical character : Biaxial -
Pleochroism : Visible
Fluorescence : None
Solubility : -
Magnetism : NoneRadioactivity : Very strong