where do intrusive rocks cool
Igneous rocks can be classified into two main categories: intrusive and extrusive. A trick to help kids remember intrusive and extrusive is to think of in trusive -- in side and ex trusive -- ex it. Intrusive rocks come from magma. They cool slowly deep in Earth's crust. When magma cools underground, the crust acts like a blanket, insulating it, keeping it warm longer. Because the magma cools slowly, crystals of different minerals have time to grow.