What are rocks formed by the cooling of molten rock called?

Rocks formed by the cooling and solidification of molten rock are known as igneous rocks. This formation process can occur beneath the Earth's surface, resulting in intrusive or plutonic igneous rocks, or at the surface following volcanic activity, resulting in extrusive or volcanic igneous rocks. The distinctive characteristic of igneous rocks is that they are directly derived from magma or lava, which, upon cooling, crystallizes into solid rock.

Sedimentary rocks form from the accumulation and compaction of mineral and organic particles over time, while metamorphic rocks result from the transformation of existing rocks under pressure and temperature without melting. Unfoliated rocks, often a classification of metamorphic rock, do not exhibit a layered or banded appearance but are still not formed from molten rock.

Understanding the formation processes helps in correctly identifying each rock type and appreciating the dynamic processes that shape the Earth's geology.