ROUBAULTITE

    Class : Carbonates, nitrates, borates
    Subclass : Uranyl carbonates
    Crystal system : Triclinic
    Chemistry : Cu2(UO2)3(CO3)2O2(OH)2 4H2O
    Rarity : Very rare

Roubaultite is an extremely rare copper and uranium carbonate, known only in the oxidation zone of three uranium deposits, notably in Kantanga (Democratic Republic of Congo). It was named in honor of Marcel Edouard Roubault, Professor of Geology at the University of Nancy and author of the excellent "Détermination des minéraux des roches au microscope polarisant". Roubaultite occurs in small green lamellar crystals gathered in rosettes of 3 mm maximum. It is associated with becquerelite and soddyite on pitchblende in the process of alteration.

Main photo : Roubaultite from KOV Open cut, Kamoto, Democratic Republic of Congo © Italo Campostrini

Roubaultite in the World

Roubaultite is an exclusively Congolese mineral, it is found in Shinkolobwe, but also in Musonoï and KOV Open cut near Kamoto.

Right photo : Roubaultite from Musonoï, Kolwezi, Democratic Republic of Congo © Paul de Bondt


Roubaultite in France

Roubaultite is not present in the French underground.

Twinning

No twinning known for this mineral species.

Fakes and treatments

No fakes listed for this mineral species.


Hardness : 3
Density : 5.02
Fracture : Irregular
Streak : Undetermined

TP : Translucent to transparent
RI : 1.700 to 1.830
Birefringence : 0.130
Optical character : Biaxial +
Pleochroism : Visible
Fluorescence : None

Solubility : -

Magnetism : NoneRadioactivity : Very strong