Definition: Schist

Etymologically, "that which can be split". Clay compacted by sediment pressure and, above all, by lateral orogenic thrust. Any rock that can be split into sheets, such as slate. Schist soils produce the best Riesling in the Moselle region of Germany, in Alsace, the best Banyuls in Roussillon and the finest Ports in the Douro region of Portugal. These layered rocks are generally the result of the early stages of metamorphism of clayey rocks.