Section 4-2 How are igneous rocks formed? What is the difference between magma and lava? What is the difference between intrusive and extrusive rocks? Describe the 3 types that igneous rocks can be classified into.

Igneous rocks are formed when molten material from a volcano or from deep inside the Earth cools and hardens. Magma is molten rock that is beneath the Earth’s surface and lava is magma that has reached the Earth’s surface and flows from a volcano.

Intrusive rocks are igneous rocks that form below the Earth’s surface. They cool slowly and have large mineral grains. Extrusive rocks are igneous rocks that form when lava cools on or near the Earth’s surface. They cool quickly and have a fine-grained texture. Sometimes the lava cools so quickly that air bubbles get trapped in the lava leaving behind holes in the rock.

Types of Igneous Rocks Basaltic – are dense, heavy, and dark-colored; are rich in iron and magnesium; are produced by Hawaiian volcanoes Granitic – are light-colored and less dense; contains a lot of silicon and oxygen; can cause violent volcanic eruptions Andesitic - have mineral compositions between basaltic and granitic

Igneous rocks are the most abundant type of rock on Earth. Basaltic Granitic Andesitic Igneous rocks are the most abundant type of rock on Earth.