Typically rocks formed<span> by </span>regional metamorphism<span> have experienced deviatoric stress producing foliations. </span>Rock<span> types such as slate, phyllite, schist, gneiss and granulite are typical of </span>regional metamorphism<span>. </span>Low-grade metamorphism takes place at temperatures between about 200 to 320oC, and relatively low pressure. Low grade metamorphic rocks are generally characterized by an abundance of hydrous minerals.<span> With increasing grade of metamorphism, the hydrous minerals begin to react with other minerals and/or break down to less hydrous minerals.</span>
