Verditer.

Verditer. This pigment is a hydrated oxide of copper formed by adding lime to a solution of a salt of this metal, such as the nitrate, when a blue precipitate is thrown down. This blue verditer is scarcely injured by light, but it is blackened by impure air. It is used in common distemper painting and in paper-staining. Green verditer is the blue pigment changed to green by boiling, but it is a colouring substance of little value.