ellsworthite

ellsworthite

[′elz·wər‚thīt] (mineralogy) (Ca,Na,U)2(Nb,Ta)2O6(O,OH) A yellow, brown, greenish or black mineral of the pyrochlore group occurring in isometric crystals and consisting of an oxide of niobium, titanium, and uranium. Also known as betafite; hatchettolite.