A fine-grained metamorphic rock with a foliation caused by the preferred orientation of very fine-grained mica.
A metamorphosed mudstone with a silky sheen.
A fine-grained, foliated metamorphic rock intermediate between mica schist and slate; not as tough as slate. Mica crystals give a silky sheen to the cleavage surface.
Silvery, gray to dark-gray, fine- to very fine-grained, schist-like metamorphic rock.
a clay bearing rock with a silky sheen that has been subjected to a low grade of metamorphism.
Fine grained metamorphic rock with well developed cleavage, derived from shale.
foliated metamorphic rock that develops from slate and is marked by a silky sheen and medium grain size.
A very fine-grained, foliated metamorphic rock, generally derived from shale or fine-grained sandstone. Phyllites are usually black or dark gray; the foliation is commonly crinkled or wavy. Differs from less recrystallized slate by its sheen, which is produced by barely visible flakes of muscovite ( mica).
a metamorphic rock intermediate between slate and mica schist. It has a silky sheen on undulating cleavage surfaces.
Fine-grained low-grade metasedimentary rock intermediate in metamorphic-grade between a slate and a schist.
a metamorphosed rock formed from silstones and mudstones in which surfaces exhibit a lustrous sheen caused by newly formed small crystals of mica and chlorite
When a clay is metamorphosed by heat and pressure beyond the stage of a slate, it forms phyllite. The surfaces becomes 'silky' and rather than splitting along parallel planes, it splits into 'leaf' shaped lenses. (Phyllos is Greek for 'leaf'.)
A general term for minerals with a layered crystal structure; also a metamorphosed rock, intermediate in grade between slate and mica schist.
Contains platy minerals too small to be clearly identifiable, distinguished by a glossy sheen.
a low-grade metamorphic rock, intermediate between shale and schist and consisting chiefly of mica or chlorite. [AHDOS
Phyllite is a type of foliated metamorphic rock primarily composed of quartz, sericite mica, and chlorite; the rock represents a gradiation in the degree of metamorphism between slate and mica schist. Minute crystals of graphite, sericite, or chlorite impart a silky, sometimes golden sheen to the surfaces of cleavage (or schistosity).
