MARTHOZITE

    Class : Oxides and hydroxides
    Subclass : Uranyl selenites
    Crystal system : Orthorhombic
    Chemistry : Cu(UO2)3(SeO3)3(OH)2 7H2O
    Rarity : Uncommon

The appearance of marthozite and other uranium selenites requires the joint presence of sufficient quantities of selenium and uranium in a deposit. These conditions are only met exceptionally, which explains the great rarity of these minerals, of which there are only four (guilleminite, demesmaekerite, derriksite and marthozite). It was named in honor of Aimé Marthoz, Director General of the Union Minière du Haut-Katanga. Marthozite forms millimetric crystals flattened according to (100) often trapezoidal, from green-yellow to greenish brown. The face (001) is striped parallel to [001].

Main photo : Marthozite from Musonoi, Kolwezi, Democratic Republic of Congo © Joachim Esche

Marthozite from Musonoi, Kolwezi, Democratic Republic of Congo © Stephan Wolfsried
Marthozite from Musonoi, Kolwezi, Democratic Republic of Congo © Brent Thorne
Marthozite from Musonoi, Kolwezi, Democratic Republic of Congo © Luc Vandenberghe
Marthozite from Musonoi, Kolwezi, Democratic Republic of Congo © Joy Desor

Marthozite in the World

Marthozite is only found almost exclusively in the oxidation zone of the copper and cobalt deposit (with accessory uranium) of Musonoï (Democratic Republic of Congo). It has also been reported on the uranium deposit of La Creusaz (Switzerland) as well as in Peña Negra (Argentina).

Marthozite in France

Marthozite is not known in the French underground.

Twinning

No twins known for this mineral species

Fakes and treatments

No fakes recorded for this mineral species.


Hardness : Undetermined
Density : 4.4
Fracture : Undetermined
Streak : Undetermined

TP : Translucent
RI : Undetermined
Birefringence : Undetermined
Optical character : Biaxial -
Pleochroism : None
Fluorescence : None

Solubility : Aqua regia

Magnetism : NoneRadioactivity : Very strong