The type of rocks that form under heat and pressure are called metamorphic rocks. These rocks originate from existing igneous, sedimentary, or other metamorphic rocks that undergo significant changes due to extreme conditions of temperature and pressure. This transformation process, known as metamorphism, can alter the mineral composition and structure, resulting in different characteristics and appearance. Examples of metamorphic rocks include schist and gneiss, which display distinct foliation and banding as a result of these geological processes.