What type of rock forms under extreme heat and pressure?

Metamorphic rocks are formed through the process of metamorphism, which occurs under extreme heat and pressure conditions. This process can happen deep within the Earth's crust, where existing rocks—either igneous, sedimentary, or even other metamorphic rocks—are subjected to high temperatures and pressures that cause them to change physically and chemically without melting. The minerals within these rocks may recrystallize, and new minerals may form, resulting in a rock that can look very different from the original rock.

This transformation can lead to the development of textures such as foliation, which is the layering that may occur due to the alignment of minerals under directional pressure, or non-foliated textures, where minerals are not arranged in layers. Common examples of metamorphic rocks include schist, gneiss, and marble, which have distinct characteristics and compositions due to the conditions under which they formed.

In contrast, igneous rocks are formed from the cooling and solidification of molten material (magma or lava), while volcanic and extrusive refer specifically to the type of igneous rocks that form on the Earth’s surface from lava flows. Thus, these options do not pertain to the processes of heat and pressure that lead to the formation of metam