- a black, crystalline mineral, iron niobate, (Fe, Mn)Nb2O6, the principal ore of niobium, an end member of a series of solid solutions in which manganese and tantalum combine to form tantalite.
- a black mineral consisting of a niobium oxide of iron and manganese in orthorhombic crystalline form: occurs in coarse granite, often with tantalite, and is an ore of niobium. Formula: (Fe, Mn)(Nb) 2 O 6
