The Collaborative International Dictionary of English v.0.48:

Rhodonite \Rho"don*ite\, n. [Gr. "ro`don the rose. ] (Min.)
   Manganese spar, or silicate of manganese, a mineral occuring
   crystallised and in rose-red masses. It is often used as an
   ornamental stone.
   [1913 Webster]

WordNet (r) 3.0 (2006):

rhodonite
    n 1: a pink or red mineral consisting of crystalline manganese
         silicate; used as an ornamental stone