chalcocite

from WordNet (r) 3.0 (2006)

chalcocite
    n 1: a heavy grey mineral that is an ore of copper [syn:
         {chalcocite}, {copper glance}]

from The Collaborative International Dictionary of English v.0.48

Chalcocite \Chal"co*cite\, n. [Gr. chalko`s brass.] (Min.)
   Native copper sulphide, called also {copper glance}, and
   {vitreous copper}; a mineral of a black color and metallic
   luster. [Formerly written {chalcosine}.]
   [1913 Webster] Chalcographer