1. I. Formation
They are
formed when
hot, liquid
rock, or
magma, cools
and solidifies
(Hardens)

2. II. Classification
 Igneous rocks are classified according
to their composition and texture.
 4 basic types of textures
Glassy – black and sharp
Fine grained – interlocking pieces
Coarse grained – consist of interlocking
mineral crystals
Porphyritic – made of large crystals
scattered on the back of small crystals.

3. Igneous Rocks
Coarse-Grained Fine-Grained
Granite
Gabbro Basalt
Rhyolite

5. III. Magma vs. Lava
Magma – molten material
below the earth’s surface.
Lava – molten material
above the earth’s surface.

7. A. Intrusive Igneous
Rocks:
 Magma pushes into
surrounding rock below
the Earth’s surface
 Cools slower
 Large Crystals
 Think: (INSIDE)

8. Examples:

9. Did you know?!?!
Granite is
the most
abundant
intrusive
rock!

10. B. Extrusive Rocks:
 forms when
magma erupts
onto the Earth’s
surface (lava),
 cools quickly
 very small or no
crystals formed
 Think:
(EXTERIOR)

11. Example:
Basalt is the most
common
EXTRUSIVE
igneous rock!

12. Did you know?!?!
Another
name for
an
Extrusive
rock is a
VOLCANIC
rock

14. A Closer Look at an Igneous
Rock
Obsidian is a dark-colored volcanic glass that forms from the very rapid
cooling of molten rock material. It cools so rapidly that crystals do not form.
Is it fine-grained or
coarse-grained?
Is this rock Intrusive
or Extrusive?

15. http://www.youtube.com/watch?v
=PqgHUPSTojY
Must write down TWO things you
learned!!!!
Be prepared to share!

16. http://www.youtube.com/watch?v=rkGV
E6wNAzo
A little Science Rap