Coltan Wikipedia
Coltan (short for columbite–tantalites and known industrially as tantalite) is a dull black metallic ore from which are extracted the elements niobium and niobiumdominant mineral in coltan is columbite (after niobium''s original American name columbium), and the tantalumdominant mineral is the tantalite.. Tantalum from coltan is used to manufacture tantalum capacitors which are