1. How Are Igneous Rock Formed?

2. Igneous rocks are called fire rocks and are formed either underground or above ground

3. Underground, they are formed when the melted rock, called magma, deep within the earth becomes trapped in small pockets

4. Magma - cools slow….ly underground forming Large grains or crystals. The atoms have Time to make orderly arrangements

5. Igneous rocks can also form above ground when volcanoes erupt, causing the magma to rise above the earth's surface. It will now be called Lava

6. As the lava cools above ground it cools Quickly. The grains or crystals do not have time to form and arrange themselves

7. Quick cooling causes small grain sizes and sometimes no grain sizes at all. When grains do not take any shape at all the term used is called non-crystalline(no grains) or glassy

8. Intrusive – refers to magma that cooled slowly underground forming large grains or crystals

9. Extrusive – refers to Lava that cooled quickly above the ground it forms small-tiny grain sizes or no crystals ( ) in the rock

10. Lets look at some pictures and compare what you see to your reference table

11. http://volcano.und.edu/vwdocs/vwlessons/l essons/Slideshow/Igrocks/Igindex.htmlhttp://volcano.und.edu/vwdocs/vwlessons/l essons/Slideshow/Igrocks/Igindex.html

12. Granite

13. Gabbro

14. Rhyolite

15. Basalt

16. Scoria (vesicular – holes in it)

17. Vesicular Basalt

18. Obsidian ( non-crystalline)

19. Pumice

20. Basaltic Glass