What is the primary rock type that forms from the solidification of magma?

Igneous rock is formed through the solidification of magma, which is molten rock located beneath the Earth's surface. The process begins when magma cools and crystallizes, either within the Earth, leading to intrusive igneous rocks, or on the surface after a volcanic eruption, resulting in extrusive igneous rocks. This rock type is characterized by its crystalline texture, which reflects the cooling rate of the magma; slower cooling allows for larger crystals to form, whereas rapid cooling creates smaller crystals.

In contrast, metamorphic rocks are formed from the alteration of existing rocks due to temperature, pressure, or chemically active fluids, rather than from the solidification of magma. Sedimentary rocks originate from the compaction and cementation of sediments, which can be derived from the erosion of pre-existing rocks or the accumulation of organic material. Quartzite, specifically, is a type of metamorphic rock that forms from the recrystallization of sandstone under heat and pressure, and is not a primary rock type formed from magma. Therefore, igneous rock is distinct in its origin and formation process related to magma.