COLTAN (ColumbiteTantalite) is a dull metallic ore found in major quantities in the eastern areas of Congo. When refined, COLTAN becomes metallic Tantalum, a heatresistant powder that can hold a high electrical charge. Columbite ((Fe, Mn, Mg)(Nb, Ta) 2 O 6: Iron Manganese Magnesium Niobium Tantalum Oxide) is the most abundant niobium mineral and is used in alloys for improved strength.