GEOLOGY & PLANETARY SCIENCE A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site columbite Columbite. Credit:Smithsonian Institution A lustrous black oxide mineral of iron, manganese, and niobium [(Fe, Mn) Nb2O6]. It is the chief ore of niobium and is found mainly in Western Australia, Zaire, Madagascar, and South Dakota. Tantalum replaces niobium in all proportions up to 100% (tantalite). Columbite crystallizes in the orthorhombic system. Related category    • GEOLOGY AND PLANETARY SCIENCE Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP