Webster's 1828 Dictionary
EPIDOTE
n.[From Gr. ; so named from the apparent enlargement of the base of the prism in one direction. It is called by Werner, pistazit, and by Hausmann, thallit.] A mineral occurring in lamellar, granular or compact masses, in loose grains, or in prismatic crystals of six or eight sides, and sometimes ten or twelve. Its color is commonly some shade of green, yellowish, bluish or blackish green. It has two varieties, zoisite and aranaceous or granular epidote.
Epidote is granular or manganesian.
Webster's 1913 Dictionary
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.
New American Oxford Dictionary
epidote
ep i dote |ˈepiˌdōt ˈɛpɪdoʊt | ▶noun a lustrous yellow-green crystalline mineral, common in metamorphic rocks. It consists of a hydroxyl silicate of calcium, aluminum, and iron. ORIGIN early 19th cent.: from French épidote, from Greek epididonai ‘give additionally ’ (because of the length of the crystals ).
Oxford Dictionary
epidote
epidote |ˈɛpɪdəʊt | ▶noun [ mass noun ] a lustrous yellow-green crystalline mineral, common in metamorphic rocks. It consists of a basic, hydrated silicate of calcium, aluminium, and iron. ORIGIN early 19th cent.: from French épidote, from Greek epididonai ‘give additionally ’ (because of the length of the crystals ).
The Wordsmith Dictionary