The Collaborative International Dictionary of English v.0.48:

Baryta \Ba*ry"ta\, n. [Gr. bary`s heavy. Cf. Baria.] (Chem.)
   An oxide of barium (or barytum); a heavy earth with a
   specific gravity above 4.
   [1913 Webster]

WordNet (r) 3.0 (2006):

baryta
    n 1: any of several compounds of barium