Source : Webster's Revised Unabridged Dictionary (1913)

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}.]

Source : WordNet®

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