Nigredo, in alchemy, is the initial stage of the opus alchymicum, opus, in which the impure metal is “killed,” purified, and subsequently dissolved with the prima materia. The nigredo is associated with the color black signifying the “death” of the impure metal. A.G.H


Drury, Nevil. The Watkins Dictionary of Magic. London. Watkins Publishing. 2005. p. 208