This rock contains quartz, feldspar, and biotite and muscovite micas. Folded schist is characterized by small-scale folds accentuated by glittering, mica crystals.

TEXTURE A medium-grained rock, the constituent minerals are often segregated into distinct bands. Schistosity, a wavy foliation caused by the rock splitting along planes of weakness, is emphasized by the mica crystals.

ORIGIN Formed by moderate pressures and low to moderate temperatures very deep in the crust within fold mountain belts.

Group: METAMORPHIC

Origin: Mountain ranges

Grain size: Medium

Classification: Regional

Pressure: Moderate

Temperature: Low to moderate

Structure: Foliated

Lamprophyre