The predominant rocky type found on Earth's crust is igneous rock. Igneous rocks form from the cooling and solidification of molten material called magma or lava. When magma cools slowly beneath the Earth's surface, intrusive igneous rocks like granite are formed. Conversely, when lava cools quickly on the surface, extrusive igneous rocks such as basalt are created. Igneous rocks make up a significant portion of the Earth's crust and are fundamental in understanding geological processes, including the formation of mountain ranges and volcanic activity. Their mineral compositions provide insights into the Earth's interior dynamics.