Dictionary
blue' vit'riol
Chem., Mineral.
a salt, copper sulfate, CuSO
4·5H
2O, occurring naturally as large transparent, deep-blue triclinic crystals, appearing in its anhydrous state as a white powder: used chiefly as a mordant, insecticide, fungicide, and in engraving. Also called
blue copperas, chalcanthite, cupric sulfate. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.