Lava Molten or partially molten rock material and dissolved gases. Lava is molten rock which has erupted at Earth's surface. Whether or not the rock has holes, or vesicles , in it. A rock with lots of vesicles has a vesicular texture. Intrusive rocks cool slowly because they solidify inside the Earth.
Extrusive rocks cool rapidly because they solidify at Earth's surface.
Igneous rocks are also classified by their chemical compositions. Darker than felsic, lighter than mafic. Usually dark-colored, but high olivine content can lend green colors. Other rare colors can be found. Magma forms from melting rock.