Formula: Ba(UO₂)₂(VO₄)₂ · 5H₂O

Species:

Colour: Lemon-yellow, yellow-orange, orange, greenish yellow, green, brown

Hardness: 3

Specific Gravity: 4.55

Crystal System: Orthorhombic

Member of: Francevillite Group, Curienite-Francevillite Series.

Name: Named in 1957 by G. Branche, M.E. Ropert, F. Chantret, B. Morignat, and R. Pouget for Franceville, the city nearest the type locality.

Type Locality: Mounana Mine (Mouana Mine), Mounana, Léboumbi-Leyou Department, Haut-Ogooué Province – Gabon