Final answer:
Molten material hardens and forms rocks through the process of cooling and solidification. Igneous rocks form when magma cools, while metamorphic rocks form from pre-existing rocks altered by heat and pressure.
Step-by-step explanation:
Igneous rocks are formed when molten material, called magma, cools and becomes solid. This can happen either inside or outside the Earth. When magma cools below the Earth's surface, it forms intrusive igneous rocks. These rocks cool gradually and slowly, allowing individual crystals to grow large. For example, feldspar, a pink to white blocky mineral, crystallizes early in the cooling process and has straight crystal sides. Quartz, a clear and glassy mineral, crystallizes later and fills spaces.
Metamorphic rocks, on the other hand, are formed when pre-existing rocks are altered by heat and/or pressure. The sources of heat for metamorphism are magma chambers and the geothermal gradient. Pressure also increases with depth in the Earth, especially during tectonic plate collisions. Metamorphic rocks are found in mountain belts or ancient mountain belts.
Molten material hardens and forms rocks through the process of cooling and solidification. This process can occur inside the Earth or at the surface. Igneous rocks form when magma cools and becomes solid. Metamorphic rocks form when pre-existing rocks are altered by heat and pressure. These processes shape the Earth's surface and contribute to the formation of different types of rocks.