WYARTITE

    Class : Carbonates, nitrates, borates
    Subclass : Uranyl carbonates
    Crystal system : Orthorhombic
    Chemistry : Ca3U(UO2)6(CO3)2(OH)18 4H2O
    Rarity : Very rare

Wyartite belongs to the uranium carbonates. These minerals are present in the oxidation zone and are formed in the early stages of alteration of uraninite, but in very particular oxidation conditions which explain their great rarity. This mineral was named in honor of Jean Wyart, Professor of Mineralogy at the Sorbonne (Paris). Wyartite occurs in millimetric crystals flattened on (001), elongated along [010] and striated following this elongation, often grouped in flabelliform clusters. Its color is black to purplish black, rarely brown-green. It occupies cavities in uraninite in association with rutherfordine and wolsendorfite. It is a mineral that oxidizes easily into schoepite, which is yellow-brown in color.


Main photo : Wyartite from Shinkolobwe, Democratic Republic of Congo © Uwe Haubenreisser

Wyartite in the World

The best samples of wyartite come from Shinkolobwe (Democratic Republic of Congo), it is also known at Ranger Mine (Australia) and Jodhpur (India).

Right photo : Wyartite from Shinkolobwe, Democratic Republic of Congo © Uwe Haubenreisser


Wyartite in France

In France, wyartite is reported at the Limouzat mine in the Bois Noirs (Loire).

Twinning

No twinning known for this mineral species.

Fakes and treatments

No fakes listed for this mineral species.


Hardness : 3 to 4
Density : 4.69
Fracture : Undetermined
Streak : Brown-purple

TP : Opaque to transparent
RI : 1.890 to 1.910
Birefringence : 0.020
Optical character : Biaxial -
Pleochroism : Strong
Fluorescence : None

Solubility : -

Magnetism : NoneRadioactivity : Very strong