epidote

Ep"i*dote, n. Etym: [Gr. épidote. So named from the enlargement of the base of the primary, in some of the secondary forms.] (Min.) Defn: 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. Note: The Epidote group includes ordinary epidote, zoisite or lime epidote, piedmontite or manganese epidote, allanite or serium epidote.

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