Dictionary
mercu'ric sul'fide
Chem.
a crystalline, water-insoluble, poisonous compound, HgS, occurring as a coarse, black powder
(black mercuric sulfide) or as a fine, bright-scarlet powder
(red mercuric sulfide) : used chiefly as a pigment and as a source of the free metal.
Also,mercury sulfide.Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.