1. Rocks: Mineral Mixtures

2. Section 1: Understanding Rock
What exactly is rock?
A solid mixture of crystals of one or more minerals, that range in all sizes from pebbles to formations that are thousands of kilometers long.

3. The Value of Rock Rock is an important natural resource.
Used by early humans to make tools such as hammers, spears, knives, and scrapers.
Used for centuries to make buildings, roads, and monuments.
Certain types of rocks have helped build ancient and modern civilizations.
Rock study has helped scientists to discover the history of life on Earth.

4. Machu Picchu, Peru 600 A.D. Ancient Civilization Rock Structure

5. Fossils
Help provide information of life forms that lived thousands of years ago.

6. The Rock Cycle
Rocks in the Earth’s crust are constantly changing shape and composition.
The way the rock forms determines the type of rock that it is.
The three main types of rocks are: igneous, sedimentary, and metamorphic.

7. Types of Rocks There are three main types of rocks:
Igneous - formed when molten rock cools.
Sedimentary – formed by the “cementing together” of small grains of sediment.
Metamorphic – rocks changed by the effect of heat and pressure.

8. Igneous Rocks
These are rocks formed by the cooling of molten rock (magma.)
magma
volcano
Magma cools and solidifies forming igneous rocks

9. Sedimentary Rocks
Sedimentary Rocks are rocks formed when particles of sediment build up and are “cemented together” by the effect of pressure and minerals.
Getting older
sea
Fragments washed to the sea
Sedimentary
rocks
Rocks are broken
up by the action
of weather

10. Metamorphic Rocks
Metamorphic rocks are formed by the effect of heat and pressure on existing rocks.
This can greatly affect the hardness, texture or layer patterns of the rocks.
Magma
Pressure from surface rocks
metamorphic
rock
forming
here
heat

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