Source : Webster's Revised Unabridged Dictionary (1913)

Tantalite \Tan"ta*lite\, n. [Cf. F. tantalite.] (Min.)
   A heavy mineral of an iron-black color and submetallic
   luster. It is essentially a tantalate of iron.

Source : WordNet®

tantalite
     n : a mineral consisting of tantalum oxide of iron and manganese
         that occurs with niobite or in coarse granite; an ore of
         tantalum