The Collaborative International Dictionary of English v.0.48:

Malachite \Mal"a*chite\, n. [Fr. Gr. mala`chh a mallow, from its
   resembling the green color of the leaf of mallows: cf. F.
   malachite. Cf. Mallow.] (Min.)
   Native hydrous carbonate of copper, usually occurring in
   green mammillary masses with concentric fibrous structure.
   [1913 Webster]

   Note: Green malachite, or malachite proper, admits of a high
         polish, and is sometimes used for ornamental work. Blue
         malachite, or azurite, is a related species of a deep
         blue color.
         [1913 Webster]

   Malachite green. See Emerald green, under Green, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

malachite
    n 1: a green or blue mineral used as an ore of copper and for
         making ornamental objects