1. Igneous Rocks Chapter 3.2 ©Mark Place, 2007-2008

2. Formation Form when magma or lava cools and hardens.
Magma: inside Earth
Lava: outside Earth

3. Where they are made? http://www.indiana.edu/~geol116/week3/maggran.mov
INTRUSIVE IGNEOUS ROCKS
Inside Earth

4. EXTRUSIVE IGNEOUS ROCKS * Outside Earth

6. Texture of the Rocks? Igneous rocks have different textures.
Texture is how a rock looks and feels.
Texture is based on the size of crystal grains in the rock.

7. Crystal Size is Determined by:
cooling time

8. crystal size
cooling time

9. Large Crystals Indicate
long cooling time
Small Crystals Indicate
short cooling time

10. SLOW cooling-large enough crystals to see with your naked eye
Intrusive
Extrusive
form on or near the surface
QUICK cooling -small or no crystals
form below the
surface
SLOW cooling-large enough crystals to see with your naked eye

11. Characteristics used to classify igneous rocks

12. Texture
glassy }
extrusive
fine

13. Texture
coarse }
intrusive
very coarse

14. Porphyrytic: When you have a mix of large and small crystal grains.
This rock experienced two
cooling situations.