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 from Monument No. 2 Mine, Arizona, USA © Douglas Merson
Metatyuyamunite from Mashamba West Mine, D.R. Congo © Pascale & Daniel Journet
Metatyuyamunite from Veta Mad Mine, Colorado, USA © Alex Earl
Metatyuyamunite from Mashamba West Mine, DR Congo © Harold Moritz

Metatyuyamunite in the World

The best metatyuyamunite crystals measure 3 mm and come from the Mashamba West mine (Katanga, Democratic Republic of Congo) where it accompanies malachite. It is also found on uranium deposits in Utah, Arizona and Colorado.

Metatyuyamunite in France

Metatyuyamunite is not present in the French underground.

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