Definition of epidote in English:



mass noun
  • A lustrous yellow-green crystalline mineral, common in metamorphic rocks. It consists of a basic, hydrated silicate of calcium, aluminium, and iron.

    • ‘Along the contact zone the limestones were recrystallized into a cloudy white, massive calcite containing grossular, epidote, magnetite, quartz, and tremolite.’
    • ‘Iron was remobilized and limned specular hematite, along with epidote, actinolite/tremolite, and andradite.’
    • ‘These crystals are associated with chalcopyrite, galena, quartz, calcite, epidote, and chlorite.’
    • ‘Biotite and epidote occur as secondary minerals.’
    • ‘All five rock samples are mineralogically simple, and comprise mainly muscovite, quartz and feldspar with accessory epidote and biotite.’
    • ‘The sphalerite is associated with needle quartz, microcrystals of yellow-green epidote, and small spheres of a member of the chlorite group.’
    • ‘Biotite, epidote and clinopyroxene are also occasionally present, whereas garnet is virtually absent.’
    • ‘The matrix is dominantly felsic, but also contains biotite, muscovite, epidote and titanite.’
    • ‘A variety of minerals were deposited in the hollow vesicles, including chlorite, prehnite, quartz, epidote, microcline, and pumpellyite.’
    • ‘Fine lustrous epidote crystals to 15 cm long have been collected at the Julie claim near Hawthorne, Mineral County, Nevada.’
    • ‘Some calcareous veins contain epidote, titanite and apatite.’
    • ‘Biotite is sometimes pseudomorphed by chlorite and epidote, and garnet is absent.’
    • ‘Most such specimens are partially coated with a druse of calcite, epidote, and small, clear needle quartz crystals.’
    • ‘Large titanite euhedra are abundant along with apatite and zircon, with allanite and epidote less so.’
    • ‘Attempts to separate hornblende from these diorites to date them failed utterly because of the intensive alteration of the hornblende to chlorite and epidote.’
    • ‘Cementation is dominantly by chlorite, with epidote and zeolites also present as cement phases.’
    • ‘Coarse - to fine-granular aggregates and massive epidote are relatively common.’
    • ‘Other minerals that are present in this zone include pyrite and epidote.’
    • ‘The greenish-colored vein averages 2-4 feet in width and is composed of epidote, quartz, and calcite.’
    • ‘In addition some also contain hornblende and epidote, the latter in part replacing biotite.’


Early 19th century from French épidote, from Greek epididonai ‘give additionally’ (because of the length of the crystals).