Metamorphic rocks are formed from both sedimentary and igneous rocks by transformations due to heat and pressure at depth in the crust; unless very intense, these transformations do not totally obliterate the primary igneous or sedimentary features.

• 变质岩通常由沉积岩和火成岩受到地壳深处的地热和压力影响而变化形成，除非转变非常强烈，一般都不会完全去除火成岩和沉积岩的主要特征。