1. Test Retakes Only those that have turned in completed Vocab sheets
You need to arrange with me if you want to retake the test
If you do not want to retake, then I will replace your lowest daily grade with a 100 for doing the work.

2. Rocks Pretest

3. Who cares about Rocks?

4. What is a rock?

5. Igneous Rocks

6. Igneous Basics-
Comes from “Ignis” meaning fire. Similar to Ignition, Ignite
Two broad groups
Intrusive – Formed IN the earth from magma. Most of the time as magma rises, it cools before reaching the surface
Extrusive- Forms on the surface when magma EXITS and becomes lava (Volcanoes, New islands, etc)

7. Classification- Texture
What is texture?
Size, shape, and arrangement of its parts
Slow Cooling = Large Crystals
Quick Cooling = Small or no crystals

8. Texture Terms
Phaneritic (Coarse Grained)- The grains are large enough to see without magnification
Aphanitic (Fine Grained)- The grains are too small to see, cannot tell different minerals are in it without magnification
Porphyritic- Mixture of large and small grains (crystals formed intrusively, magma covered them and cooled quickly extrusively)

9. Texture Terms
Glassy- No crystal structure, cooled too quickly for them to form
Cellular- No crystal structure but have “cells” due to gas escaping from them when formed leaving holes

10. Composition - Types of Magma
Felsic – Combination of Feldspar and Silica (usually quartz)
Mafic – Combination of Magnesium and Ferrum (Latin for Iron)
Ultra Mafic – Very low amounts of silica and typically over 90% Mafic

11. Composition - Granitic
Generally light colored, mostly quartz and feldspar (remember these are the most common minerals overall)
10-25% dark silicates
Most of the crust is made of granitic rock
Granite is course grained version
Rhyolite is fine grained version

12. Composition – Basaltic (Gabbro)
Contain at least 45% Mafic (magnesium + iron) dark silicates
Generally dark colored, and dense
Gabbro – Course grained
Basalt – Fine grained

13. Composition - Andesitic
These are the in between of Granitic and Basaltic.
Contain 25 to 45 percent dark silicates
Diorite is coarse grained
Andesite is fine grained

14. Summary-
Dark Silicate Minerals
10-25%
25-45%
45-90%
Over 90%