Niobium ores /naɪˈoʊbiəm ɔrz/ (a. niobium ores; n. Nioberze; f. minerais de niobium; i. minerales de niobio) are natural mineral formations containing niobium. The main ore minerals of niobium are: pyrochlore (40-80% Nb2O5), columbite (50-78% Nb2O5) and loparite (7-20% Nb2O5). Niobium ores often contain tantalum impurities