- a black, crystalline mineral, iron tantalate, (Fe, Mn) Ta2O6, the principal ore of tantalum and an end member of a series of solid solutions in which manganese and niobium combine to form columbite.
- a heavy brownish mineral consisting of a tantalum oxide of iron and manganese in orthorhombic crystalline form: it occurs in coarse granite, often with columbite, and is an ore of tantalum. Formula: (Fe,Mn)(Ta,Nb) 2 O 6
