barytes

from WordNet (r) 3.0 (2006)

barytes
    n 1: a white or colorless mineral (BaSO4); the main source of
         barium [syn: {heavy spar}, {barite}, {barytes}, {barium
         sulphate}]

from The Collaborative International Dictionary of English v.0.48

Barytes \Ba*ry"tes\, n. [Gr. bary`s heavy: cf. Gr. bary`ths
   heaviness, F. baryte.] (Min.)
   Barium sulphate, generally called {heavy spar} or {barite}.
   See {Barite}.
   [1913 Webster]