sentence: Most schists are mica schists, but graphite and chlorite schists are also common.
sentences_before: Most schists have been derived from clays and muds which have passed through a series of metamorphic processes involving the production of shales, slates and phyllites as intermediate steps. Certain schists have been derived from fine-grained igneous rocks such as basalts and tuffs.
concept_name: schist
headings: Schist
categories: Metamorphic rocks