1. How are Rocks classified
Chapter 7 Lesson 2
Pages

2. Igneous Rock p. 274
Igneous rock is rock that is formed when melted rock hardens.
Magma is melted rock inside the Earth.
Lava is melted rock at the Earth’s surface.
Crystallization is the hardening of magma into rock.

3. Igneous Rock p. 274 Intrusive
Intrusive rock cools underground, deep within the Earth’s crust.
Characteristics of intrusive igneous rock:
--Intrusive rocks cooled slowly.
--Intrusive rocks have large crystals.
--These rocks have coarse texture.
Examples: Granite and Diorite

4. Intrusive
Granite

5. Intrusive
Diorite

6. Igneous Rock p. 274 Extrusive
Extrusive igneous rock is rock that cools on the Earth’s surface.
Extrusive rock cools quickly on the surface.
Extrusive rock has fine grains or even no crystals at all and
looks glassy
Examples: Obsidian, Pumice and Rhyolite

7. Igneous
Obsidian

8. Igneous
Rhyolite

9. Igneous
Pumice

10. Sedimentary Rock p. 276
Sedimentary rock is rock that forms when layers of sediment settle and bind together.
There are two main groups of sedimentary rock,
Clastic and Chemical

11. Sedimentary Rock p. 276 Clastic
Clastic-The word comes from the Greek word that means “broken”.
Process begins when rock is broken through weathering.
Wind and water move sediment to new places, layers build up; minerals bind layers.
Layers are pressed and cemented together.
Clastic rocks are classified by size of particle.

12. Sedimentary Rock p. 276 Clastic
Examples of clastic sedimentary rock
Fine particles form shale.
Medium particles form sandstone.
Coarse pebble-sized particles with smooth edges form conglomerates.

13. Sedimentary
Shale

14. Sedimentary
Sandstone

15. Sedimentary
Conglomerate

16. Sedimentary Rock p. 276 Chemical
Chemical sedimentary rocks form when chemicals in water come out of the water (evaporate) and form solids.
Example: Limestone (may contain fossils)

17. Sedimentary
Limestone

18. Metamorphic Rock p. 278 - Meta means “change”.
How metamorphic rock is made:
Igneous or sedimentary rock is changed by
PRESSURE
HEAT – high temperature, very hot water
BOTH

19. Metamorphic Rock p. 278
Metamorphism is the process by which rock is changed into metamorphic rock.
The main cause is high temperature-deep inside the Earth or in lava/magma.
Minerals melt and then crystalize into new minerals.

20. Metamorphic Rock p. 278
Regional Metamorphism takes place over a large area
Mountain building
Contact metamorphism changes a smaller area by magma or lava touching rock and changing the rock that was touched.

21. Metamorphic Rock p. 278 Examples Shale becomes SLATE.
Slate becomes SCHIST.
Schist becomes GNEISS.
Limestone becomes MARBLE.

22. Metamorphic
Shale becomes SLATE.

23. Metamorphic
Slate becomes SCHIST.

24. Metamorphic
Schist becomes GNEISS.

25. Metamorphic
Limestone becomes MARBLE.

26. Uses of Rock p. 280 Rock Use Granite Buildings Sandstone Glass
Obsidian
Jewelry, blades (in history)
Pumice
Cleaning products
Shale
Construction
Mudstone
Marble
Buildings and sculptures
Slate
Roofs, floors, chalkboards