Source : Webster's Revised Unabridged Dictionary (1913)

Columbite \Co*lum"bite\, n. [Cf. F. colombite. See {Columbium}.]
   (Min.)
   A mineral of a black color, submetallic luster, and high
   specific specific gravity. It is a niobate (or columbate) of
   iron and manganese, containing tantalate of iron; -- first
   found in New England.

Source : WordNet®

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