MASUYITE

    Class : Oxides and hydroxides
    Subclass : Uranyl hydroxides
    Crystal system : Orthorhombic
    Chemistry : Pb3U8O27 10H2O
    Rarity : Very rare

Masuyite is an extremely rare hydrated oxide of lead and uranium. It is a secondary mineral formed by oxidation of uraninite, which is found in uranium deposits along with other secondary uranium minerals (becquerelite, fourmarierite, uranophane, etc...). It was named in honor of the Belgian geologist Gustave Masuy, a specialist in Congo minerals. Masuyite forms tabular pseudohexagonal crystals not exceeding 3 mm, red-orange to carmine red in color.

Main photo : Masuyite from Shinkolobwe, Katanga, Democratic Republic of Congo © Stephan Wolfsried

Masuyite from Shinkolobwe, Katanga, Democratic Republic of Congo © Uwe Haubenreisser
Masuyite from Shinkolobwe, Katanga, Democratic Republic of Congo © Christophe Boutry
Masuyite from Shinkolobwe, Katanga, Democratic Republic of Congo © Italo Campostrini
Masuyite from Svornost Mine, Jáchymov, Czech Republic © Joy Desor

Masuyite in the World

Masuyite is only present in a few deposits around the world, the most beautiful samples come from the Katangese mines of Musonoï and Shinkolobwe (Democratic Republic of Congo). It is also reported on the Jachymov uranium deposit (Czech Republic).

Masuyite in France

In France, masuyite is reported in Rabejac and Mas d'Alary (Hérault) as well as in Lachaux near Thiers (Puy-de-Dôme).

Twinning

Twins are very common on {110} and {1-30}.

Fakes and treatments

No fakes recorded for this mineral species.


Hardness : Undetermined
Density : 5.08
Fracture : Undetermined
Streak : Undetermined

TP : Translucent to transparent
RI : 1.785 to 1.917
Birefringence : 0.130 to 0.132
Optical character : Biaxial +
Pleochroism : Low
Fluorescence : None

Solubility : -

Magnetism : NoneRadioactivity : Very strong