This document summarizes the rock cycle and how different types of rocks can be transformed into one another through various geological processes. It explains that chemical and physical weathering can break down igneous and metamorphic rocks over time. The resulting sediment can then be lithified into sedimentary rock or subjected to heat and pressure to form metamorphic rock. Metamorphic rock can also weather to sediment and recrystallize as sedimentary rock, or melt to form new igneous rock. Sedimentary rock can likewise transform into igneous or metamorphic rock through heating, melting, and recrystallization deep underground.