- Extrusive rock refers to the mode of igneous volcanic rock formation in which hot magma from inside the Earth flows out (extrudes) onto the surface as lava or explodes violently into the atmosphere to fall back as pyroclastics or tuff. In contrast, intrusive rock refers to rocks formed by magma which cools below the surface.
And if men strive together, and one smite another with a stone, or with his fist, and he die not, but keepeth his bed:
Exodus 21:18 KJV