This document provides information about the three main types of rocks - igneous, sedimentary, and metamorphic rocks. It explains that igneous rocks form from the cooling of magma or lava, sedimentary rocks form from the compaction and cementation of sediments, and metamorphic rocks form from the alteration of existing rocks by heat, pressure, and chemical reactions in the Earth. It also provides examples of different rock types and how they are used.

2. What is a Rock?
• Naturally-occurring mixtures
of minerals, glass or organic
matter.

3. Types of Rocks?

4. What is the difference between
a rock and a mineral?
• Rocks are made up of ONE or
MORE minerals.

5. Once a rock is formed, does it
stay the same rock forever?
• NO!

6. • Rocks are continually changed by
many processes, such as
weathering, erosion, compaction,
cementation, melting, and cooling
• Rocks can change to and from the
three types

7. What is the process through
which rocks change?
• The Rock Cycle—earth materials change
back and forth among the different types
of rocks

8. • “Ignis” = Latin for “fire”
• Formed from the cooling of either
magma or lava
• The most abundant type of rock
• Classified according to their origin and
composition

9. ORIGIN— Where rocks are formed
• Below ground = from magma
• Usually have LARGE crystal grains
(they cooled slowly)

10. Intrinsic Igneous Rocks:
Have large or small crystals

11. Extrinsic Igneous Rocks
• Above ground = from lava
• Usually have SMALL or NO crystals
(they cooled too quickly)

12. Peridotite: How was it formed?
Give a reason for your answer.

13. Granite: How was it formed?
Give a reason for your answer.

14. Obsidian: How was it formed?
Give a reason for your answer.

15. Diorite: How was it formed?
Give a reason for your answer.

16. Basalt: How was it formed?
Give a reason for your answer.

18. • Formed from sediments
(rock fragments,
mineral grains, animal
& plant remains) that
are pressed or
cemented together.

19. • These sediments are moved by wind,
water, ice or gravity.
• Sedimentary rocks represent 7% of
the Earth’s crust, but they cover 70%
of the Earth’s surface.
• Sedimentary rocks are
fossil-carrying rocks.

20. What turns sediments into solid rock?
• Water or wind breaks down and
deposits sediment (erosion &
deposition)

21. • The heavy sediments press down on
the layers beneath (compaction)

22. Recognise this place in Egypt?

23. • Dissolved minerals flow between the
particles and cement (glue) them
together this is called cementation.

24. How can sedimentary layers help us
understand the age of fossils?
• As sedimentary rocks
are deposited, they
form horizontal
layers
• Scientists know that
the layers on top
(and the fossils in
the top layer) are
YOUNGER than the
fossils in lower
layers.

25. • Rocks that have changed due to
intense temperature and pressure
• “Meta” means “change” and morphosis
means “form” in Greek
• Igneous, sedimentary and other
metamorphic rocks can change to
become metamorphic rocks

26. What occurs in the Earth to
change these rocks?
• Pressure from rock layers on top of it
• High heat, but not enough to melt the rock
• Rocks may be flattened or bent or chemicals
may be exchanged to form new minerals.

27. Properties of metamorphic rocks
• Usually resistant to weathering and
erosion and are therefore very hard-
wearing.
• Can be polished to give a smooth shiny
surface.
• Example: Marble, slate.

28. Examples of rocks becoming
metamorphic
• Example: marble formed from limestone

30. Magma
Igneous Rock
Sediments
Sedimentary Rock
Metamorphic Rock
Lava

32. Igneous Metamorphic Sedimentary
How is the rock
formed?
Cooling of magma Rocks reach deep parts,
changed by heat and
pressure
Compaction of
sediments under
pressure of layers
above it
Types
Intrinsic – cooled beneath the
Earth’s surface
Extrinsic - Cooled above the
Earth’s Surface
- -
Rock
appearance
Hardest, may have
crystals within it, or air
bubbles
Hard, can be polished to
be shiny
Powdery, fossils may be
found in it
Rock example
&
Uses
Granite: Kitchen
counter tops, floors
Pumice: Skin care
Marble: Statues, floors
Slate: roof tiles
Fossil age can be
estimated by studying
layers.
Limestone: used to
make cement & glass
Diagram
Types of rocks