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"Orthohombic. Habit of crystals is short prismatic; often in square prisms because of prominent development of the vertical pinacoids. Terminated by basal plane, pyramids and domes; frequently complex." — Ford, 1912

Columbite

"Orthohombic. Habit of crystals is short prismatic; often in square prisms because of prominent development…

Ferrocolumbite, also called niobite, niobite-tantalite, columbate and columbite [(Fe, Mn)(Nb, Ta)2O6] is a black mineral that is an ore of niobium and tantalum. It has a submetallic luster and a high specific gravity and is a niobate of iron and manganese, containing tantalate of iron. This mineral was first found at Haddam, Middlesex County, Connecticut in New England, USA. It forms a series with the tantalum-dominant analogue Ferrotantalite and one with the manganese-dominant analogue Manganocolumbite.

Ferrocolumbite

Ferrocolumbite, also called niobite, niobite-tantalite, columbate and columbite [(Fe, Mn)(Nb, Ta)2O6]…