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
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