The type of rock formed from the cooling of molten magma is called igneous rock. Igneous rocks can form either beneath the Earth's surface, where they cool slowly and develop large crystals (intrusive igneous rocks, like granite), or above the surface from lava that cools quickly, resulting in small crystals (extrusive igneous rocks, like basalt). These rocks are fundamental components of the Earth's crust and play a critical role in the rock cycle, influencing the geology and landscape of the planet.