Igneous rocks are rocks that form from magma or lava.
Igneous rocks are classified according to their texture, origin, and mineral composition.
Origin
Intrusive rock is a type of rock formed beneath the earth's surface.
Extrusive rock is a type of rock formed from lava on the earth's surface.
Texture and Mineral Composition
Rapidly cooling lava forms fine-grained igneous rocks with small crystals.
Igneous rocks formed beneath the earth's surface have a coarse mineral texture.