the crystal size of intrusive igneous rock is large
More time is spent in the solidification phase as the magma or lava cools, allowing crystals to grow larger.
because of the cooling speed
Extrusive igneous rock is found outside the Earth's crust. Intrusive, however, is found underneath the Earths crust
Think about this: When molten rock cools slowly, bigger crystals are created.Then think about this: Intrusive rocks cool quite slowly because they are created in the earth's crust.So... Intrusive...