1. Igneous Rocks!

2. Igneous Rock so they are called crystalline
Forms when magma cools and becomes solid
Are made of crystals…
so they are called crystalline

3. Rock Textures Coarse-grained Fine-grained
Cooled very slowly so large crystals could grow
Ex – granite
Fine-grained
Cooled quickly so large crystals did not have time to form
Ex - basalt

4. Other Textures Porphyritic Glassy Vesicular
Mixture of small and large crystals
Ex - granite
Glassy
Magma very viscous, cooled quickly
Ex - obsidian
Vesicular
Cooled quickly, full of holes
Ex - pumice

5. Rock Composition Felsic Mafic Intermediate
Contains a large amount of silica
Usually lighter color
Mafic
Contains much less silica
Usually darker color
Intermediate

6. Rock Structures Intrusive Rock Extrusive Rock Forms underground
It is “in” the ground
Extrusive Rock
Forms on the Earth’s surface
It has “exited” the ground

7. Intrusive Igneous Rock
Intrusive rocks cool slower, so their crystals tend to be larger

8. Intrusive Igneous Rocks

9. Extrusive Igneous Rock
Extrusive rocks tend to cool quicker so the crystals are generally smaller
Volcanic
Neck

10. Extrusive Igneous Rock
Shiprock, New Mexico

11. Extrusive Igneous Rock