Francevillite

Francevillite is a uranyl-group vanadate mineral in the tyuyamunite series.

Its chemical formula is (Ba,Pb)(UO2)2V2O8·5(H2O).

[2] Francevillite occurs in the oxidized zone of a lead-bearing uranium–vanadium deposits.

[2] Francevillite was first described in 1957 for an occurrence in its type locality of the idle Mounana uranium mine, near Franceville, Haut-Ogooué, Gabon and was named for the city.

At other localities, francevillite is associated with duttonite, vanuralite, mottramite, carnotite, dewindtite, torbernite, uranopilite, johannite and kasolite.