From The Collaborative International Dictionary of English v.0.48 :
Rhodochrosite \Rho`do*chro"site\, n. [Gr. "ro`don the rose + ???
a coloring.] (Min.)
Manganese carbonate, a rose-red mineral sometimes occuring
crystallized, but generally massive with rhombohedral
cleavage like calcite; -- called also dialogite.
[1913 Webster]
From WordNet (r) 3.0 (2006) :
rhodochrosite
n 1: a mineral consisting of manganese carbonate; a source of
manganese