Source : Webster's Revised Unabridged Dictionary (1913)

Greenockite \Green"ock*ite\, n. [Named after Lord Greenock.]
   (Min.)
   Native cadmium sulphide, a mineral occurring in yellow
   hexagonal crystals, also as an earthy incrustation.

Source : WordNet®

greenockite
     n : ore of cadmium; a rare yellowish mineral consisting of
         cadmium sulphide in crystalline form [syn: {cadmium
         sulphide}]