Igneous rocks are formed 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, such as granite. Conversely, when lava cools quickly on the surface, it forms extrusive igneous rocks, like basalt. These rocks are classified based on their mineral composition and texture. Igneous rocks can be further divided into two main categories: felsic, which are rich in silica and lighter in color, and mafic, which contain less silica and are darker. Understanding igneous rocks helps geologists learn about Earth's geological processes.