1. Ch4 Sec2 Igneous Rock

2. Key Concepts What characteristics are used to classify igneous rock? How are igneous rocks used?

3. Key Terms Extrusive rock Intrusive rock Silica

4. Ch4 Sec2 Classifying Igneous Rocks – Igneous rocks are classified according to their origin, texture, and mineral composition – Extrusive rock: is igneous rock formed from lava that erupted onto Earth’s surface – Intrusive rock: igneous rock that formed when magma hardened beneath Earth’s surface – Silica: a material formed from oxygen and silicon

5. Ch4 Sec2 Uses of Igneous Rocks – People throughout history have used igneous rock for tools and building materials