Vocabulary  Magma: hot molten rock under the Earth’s surface  Lava: hot molten rock above the Earth’s surface  Mineral: Molecules arranged in a regular pattern that are the “ingredients” of rocks.

Intrusive Igneous Rocks  Intrusive rocks are formed when MAGMA cools underground.  It is called intrusive because it INTRUDES on other rock layers

Intrusive Igneous Rocks  Intrusive rocks cool SLOWLY because they are underground where it is hotter.  Because they cool slowly they have BIGGER crystals (crystals have more time to grow).

Extrusive Igneous Rocks  Extrusive Rocks are formed when LAVA cools above the Earth’s surface.  They are called extrusive because they EXplode

Extrusive Igneous Rocks  Extrusive rocks cool more QUICKLY because they are out in the open  Because they cool more quickly they have SMALLER crystals (crystals have less time to grow).