ˈepəˌdōt noun
( -s )
Etymology: French épidote, from (assumed) Greek epidotos, verbal of Greek epididonai to give besides, increase, from epi- + didonai to give — more at date
: a yellowish green mineral Ca 2 (Al,Fe) 3 Si 3 O 12 OH consisting of a silicate of calcium, aluminum, and iron and occurring massive or in grains, columns, and monoclinic crystals (hardness 6-7, specific gravity 3.25-3.50)