1. Chapter 5 - Igneous Rocks

2. Formation Igneous rocks form from cooling magma. Igneous rocks form from cooling magma. If they cool inside the Earth, they are called __________ igneous rocks and have _______ crystals. If they cool inside the Earth, they are called __________ igneous rocks and have _______ crystals. If they cool on the surface, they are called __________ igneous rocks and have _______ crystals. If they cool on the surface, they are called __________ igneous rocks and have _______ crystals.

3. Crystal Size This piece of obsidian cooled so _____ on the surface that it did not have time to form any crystals. This piece of obsidian cooled so _____ on the surface that it did not have time to form any crystals.

4. Crystal Size This piece of rhyolite also cooled on the surface very fast and has ______ crystals. This piece of rhyolite also cooled on the surface very fast and has ______ crystals.

5. Crystal Size This piece of granite cooled _______ inside the Earth and has ______ crystals. This piece of granite cooled _______ inside the Earth and has ______ crystals.

6. Classification is based on crystal size and composition.