Igneous rock is a type of rock that forms from the cooling and solidification of molten material called magma or lava. When magma cools slowly beneath the Earth's surface, it creates intrusive igneous rocks, like granite. If lava cools quickly on the surface, it forms extrusive igneous rocks, such as basalt. These rocks are classified based on their mineral composition and texture. Igneous rocks can be found in various environments, from volcanic regions to mountain ranges. They play a crucial role in the rock cycle and are essential for understanding Earth's geological history.