The type of rock created by the cooling of magma or lava is termed igneous rock. Igneous rocks form either through the solidification of magma below the Earth's surface, resulting in intrusive igneous rocks, or through the cooling of lava on the surface, leading to extrusive igneous rocks. Examples of intrusive rocks include granite, while basalt is a common example of extrusive rock. The cooling rate influences the texture of the rock, with slower cooling producing larger crystals. Understanding igneous rock formation is essential for geology and also provides insights into Earth's geological history.