chlorite n 1: a generally green or black mineral; it occurs as a constituent of many rocks typically in the form of a flat crystal
Chlorite \Chlo"rite\, n. [Gr. ? (sc. ?), fr. chlwro`s light green.] (Min.) The name of a group of minerals, usually of a green color and micaceous to granular in structure. They are hydrous silicates of alumina, iron, and magnesia. [1913 Webster] {Chlorite slate}, a schistose or slaty rock consisting of alumina, iron, and magnesia. [1913 Webster]
Chlorite \Chlo"rite\, n. [Chlorous + -ite.] (Chem.) Any salt of chlorous acid; as, chlorite of sodium. [1913 Webster]