Question

How does crystal size compare in extrusive vs. intrusive rock? Explain the cause of this difference

Answer 1

The difference between extrusive and intrusive rocks are how they cool down. Extrusive rocks cool down quickly and are created by lava; because of this they have very small, fine-grained crystals. Intrusive rocks cool slowly beneath the surface of the earth and are created by magma; because the cooling process is very slow the rocks have very large crystals.