Columbite Group - (Fe²⁺,Mn²⁺,Mg)(Nb,Ta)₂O₆

Habit: Crystals are brownish-black, short prismatic, equant, also flat tabular black, massive. Opaque, translucent through thin edges, subMetallic Luster

Environment: An accessory mineral of granitic Pegmatites and other environments where Nb > Ta. Rarely found in alkalic Pegmatites and an alteration mineral of other Nb-rich minerals.

Etymology: Named for Columbia, source of the first specimens.

An important ore of tantalum and niobium.