Phyllite
Phyllite is a foliated metamorphic rock primarily composed of quartz, sericite mica, and chlorite. It 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). Phyllite is formed from the advanced metamorphism of slate. The protolith (or parent rock) for a phyllite is a slate. Its constituent platy minerals are larger than those in slate but are not visible with the naked eye. Phyllites are said to have a "phyllitic texture" and are usually classified as having a low grade in regional metamorphic facies. Phyllite has a pronounced tendency to split into sheets and forms under low pressures and temperatures. Phyllites are usually black, gray or greenish silver. The foliation is commonly crinkled or wavy in appearance.

Photographed by Michael P. Klimetz


MONTANA
Photographed by Michael P. Klimetz


SCOTLAND
Photographed by Michael P. Klimetz


Jurassic
Mesquite Schist

El Paso Mountains

Kern County
CALIFORNIA
Photographed by Michael P. Klimetz


Jurassic
Mesquite Schist

El Paso Mountains

Kern County
CALIFORNIA
Photographed by Michael P. Klimetz


Jurassic
Mesquite Schist

El Paso Mountains

Kern County
CALIFORNIA