Which type of rock forms through the cooling and solidification of magma or lava?

Igneous rock forms as a result of the cooling and solidification of magma beneath the Earth's surface or lava that erupts onto the surface. This process can occur either slowly, leading to the formation of large crystals in intrusive igneous rocks, or rapidly, resulting in small crystals or a glassy texture in extrusive igneous rocks.

The key distinguishing feature of igneous rocks is their formation from molten materials. When magma cools, it crystallizes into solid rock, and this process can occur both below ground when magma slowly cools or above ground after volcanic eruptions where lava quickly cools. This is fundamental to the rock cycle and is a crucial concept in understanding geological processes.

In contrast, sedimentary rocks are formed from the compaction and cementation of mineral and organic particles, while metamorphic rocks arise from the alteration of existing rocks due to temperature, pressure, or chemically active fluids. Organic rocks are primarily composed of biological material. Understanding the formation process of igneous rocks is vital for grasping the broader concepts of geology and Earth's composition.