iron in tantalite ore
Columbite - Wikipedia. Columbite, also called niobite, niobite-tantalite and columbate [(Fe, Mn)Nb 2 O 6], is a black mineral group that is an ore of niobium.It has a submetallic luster and a high density and is a niobate of iron and manganese.This mineral group was first found in Haddam, Connecticut, in the United States.It forms a series with the tantalum-dominant analogue ferrotantalite and ...