Schist is strongly foliated. It can be easliy split into thin flakes or slabs. By definition, schist contains more than 50% platy and elongated minerals such as mica and amphibole.

As with phyllite, the parent rock of schist is shale, but the metamorphism is much greater. If the parent rock would contain an abundance of silica, schist will often contain thin layers or bands of quartz and possibly feldspar.

Information provided by Patrick M. Colgan, Northeastern University
http://www.casdn.neu.edu