Ep"i*dote (?), n. [Gr. &?; to give besides; &?; over + &?; to give: cf. F. épidote. So named from the enlargement of the base of the primary, in some of the secondary forms.] (Min.) A mineral, commonly of a yellowish green (pistachio) color, occurring granular, massive, columnar, and in monoclinic crystals. It is a silicate of alumina, lime, and oxide of iron, or manganese.

&fist; The Epidote group includes ordinary epidote, zoisite or lime epidote, piedmontite or manganese epidote, allanite or cerium epidote.