METATYUYAMUNITE
Class : Phosphates, arsenates, vanadates
Subclass : Uranyl vanadates
Crystal system : Orthorhombic
Chemistry : Ca(UO2)2(VO4)2 3H2O
Rarity : Rare
Metatyuyamunite comes from the dehydration of tyuyamunite by loss of weakly bound zeolite water in the crystal structure of this mineral. It is a uranium present in the oxidation zone of uranium deposits rich in carnotite. Its name comes from the Greek meta (after) and tyuyamunite. It constitutes impregnations, powdery microcrystalline masses or coatings, it rarely appears in yellow to yellow-green lamellar crystals, which darken to dark green in the light.
Main photo : Metatyuyamunite from Mashamba West Mine, Democratic Republic of Congo © Uwe Haubenreisser
Metatyuyamunite in the World
Twinning
No twins known for this mineral species.
Fakes and treatments
No fakes recorded for this mineral species.
Hardness : 2
Density : 3.81 to 3.93
Fracture : Undetermined
Streak : Yellow
TP : Translucent
RI : 1.620 to 1.899
Birefringence : 0.245
Optical character : Biaxial -
Pleochroism : Low
Fluorescence : None
Solubility : -
Magnetism : NoneRadioactivity : Very strong