What is "billietite"

n. (context mineral English) An orthorhombic-pyramidal mineral containing barium, hydrogen, oxygen, and uranium.

Billietite is an uncommon mineral of Uranium that contains Barium. It has the chemical formula: Ba(UO)O(OH)•8HO. It usually occurs as clear yellow orthorhombic crystals. Billietite is named after Valere Louis Billiet (1903–1944), Belgian crystallographer at the University of Ghent, Ghent, Belgium.