Which type of rock is primarily formed through the cooling and solidification of magma?

Igneous rock is primarily formed through the cooling and solidification of magma. When magma, which is molten rock beneath the Earth's surface, rises to the surface and cools, it solidifies to form igneous rock. This process can occur either beneath the surface, where it cools slowly to create intrusive igneous rock, or on the surface following a volcanic eruption, where it cools quickly to form extrusive igneous rock.

In contrast, metamorphic rock is formed from existing rock types that are transformed through heat, pressure, and chemically active fluids. Sedimentary rock arises from the accumulation and compaction of mineral and organic particles over time, often in water bodies, and is not directly formed from magma. While the term "volcanic" may suggest a relation to magma, it typically refers to the process or activity related to volcanoes, which can produce igneous rock but does not directly answer the question about rock formation. Thus, igneous is the most accurate term describing rocks formed from the cooling and solidification of magma.