The Collaborative International Dictionary of English v.0.48:

niobite \ni"o*bite\, n. (Min.)
   Same as Columbite.
   [1913 Webster]

WordNet (r) 3.0 (2006):

niobite
    n 1: a black mineral that is an ore of niobium and tantalum
         [syn: niobite, columbite]