It is found in the mineral tantalite . Tantalite ( Fe , Mn ) Ta2O6 is the most important mineral for tantalum extraction . Tantalite has the same mineral structure as columbite ( Fe , Mn ) ( Ta , Nb ) 2O6 ; when there is more Ta than Nb it is called tantalite and when there is more Nb than Ta is it called columbite ( or niobite ) .