It has a submetallic cluster 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 ferro tantalite and one with the manganese-dominant analogue mangano Columbite.
The iron-rich member of the Columbite group is ferro columbite. Some tin and tungsten may be present in the mineral. Yttrium Columbite is the yttrium-rich Columbite with the formula (Y,U,Fe)(Nb,Ta)O4. It is a radioactive mineral found in Mozambique.
Columbite has the same composition and crystal symmetry (orthorhombic) as tantalite. In fact, the two are often grouped together as a semi-singular mineral series called Columbite-tantalite or Coltan in many mineral guides. However, tantalite has a much greater specific gravity than Columbite, more than 8.0 compared to columbine’s 5.2.
Columbite is also very similar to tapiolite. Those minerals have same chemical composition but different crystal symmetry: orthorhombic for Columbite and tetragonal for tapiolite. The largest documented single crystal of Columbite consisted of plates 6 millimetres (0.24 in) thick measuring 76 by 61 centimetres (30 in × 24 in).