Definition of phyllite in English:



  • A fine-grained metamorphic rock with a well-developed laminar structure, intermediate between slate and schist in degree of metamorphism.

    ‘It is composed of gneiss and migmatite that contain minor lenses of schist, marble, phyllite and quartzite.’
    • ‘Foliated rocks may be slate, phyllite, or schist according to grain size.’
    • ‘Clasts in this facies are commonly arranged into stripes of a single lithology (typically phyllite, schist, quartzite or marble) and show peaks in the angular and very angular classes.’
    • ‘The sequence comprises Lower Ordovician conglomerates and carbonates overlain by Upper Ordovician to Middle Devonian limestone with occasional phyllite and quartzite.’
    • ‘It is underlain by schist, phyllite, and quartzite, although outcrops of serpentine are common in the area.’



/ˈfiˌlīt/ /ˈfɪˌlaɪt/


Early 19th century (denoting a mineral resembling mica in appearance): from Greek phullon ‘leaf’+ -ite.