1. Essential Question: What is the composition of rocks and how are they formed?
Standards:
S6E5b. Investigate the contribution of minerals to rock composition.
S6E5c. Classify rocks by their process of formation.
S6E5d. Describe processes that change rocks and the surface of the earth.

2. Composition of Rocks Minerals
Rock fragments (smaller pieces of other rocks)
Organic matter (remains of organisms and their wastes)
Other natural materials

3. There are three types of rocks: Igneous, Metamorphic, and Sedimentary
Rocks are classified based on how they formed and their mineral composition.
There are three types of rocks: Igneous, Metamorphic, and Sedimentary

4. In comparing types of rocks, it is important to understand the term “mineral grain”.
Mineral grain describes the size, texture, and type of mineral found in rock.

5. Igneous Rock

6. Igneous Rock forms from hot molten lava or magma that cools and crystallizes

7. Igneous Rock can form below the surface
Igneous Rock can form below the surface. These igneous rocks cool slowly so the mineral grains are coarse-grained and easy to see

8. Igneous Rock can form on the surface
Igneous Rock can form on the surface. These igneous rocks cool quickly so the mineral grains are fine grained.

9. Some Igneous Rock cools so quickly that few or no mineral grains form.
Other cools so quickly that gases become trapped and later leave holes once the gases escape.

10. Igneous Rock

11. Examples of Igneous Rock
Granite
Pumice
Basalt
Obsidian

12. How do Igneous Rocks Form? Animation Igneous Rocks Video [4:15]