What type of rocks are formed when other rocks are subjected to extreme heat and pressure?

Metamorphic rocks are formed when existing rocks—either igneous, sedimentary, or other metamorphic rocks—are subjected to extreme heat and pressure over time. This process causes changes in the mineral composition and texture of the original rock without the rock melting. The original structure may become altered, and new minerals may form due to these conditions, resulting in a new type of rock.

This formation process is significant in the rock cycle, as it illustrates how rocks can change from one form to another based on environmental conditions. Unlike sedimentary rocks, which are created from the accumulation of sediments, or igneous rocks, which form from the cooling and solidification of magma or lava, metamorphic rocks undergo transformation rather than creation from scratch.

Foliated rocks are a specific type of metamorphic rock characterized by the alignment of minerals under directional pressure, but they fall under the broader category of metamorphic rocks rather than being a distinct type on their own. Thus, while they represent a subtype, the term "metamorphic rocks" encompasses all rocks created through metamorphism.