1. Minerals and Rocks
Chapter 8

2. Mineral Crystals Earth’s crust is made of rock
All rocks are made of minerals
Minerals – are natural, nonliving solid crystals that make up rocks
Each minerals has crystals made of one shape, they also have the same chemical makeup
Scientists have identified 3,000 minerals
Rocks in the Earth’s crust are only made of a few called “rock-forming” minerals

4. How to Identify a Mineral
Scientists use some of it’s physical properties:
Color
Luster
Hardness
Streak
Cleavage

5. LUSTER Luster – is the way its surface reflects light
It can be dull, metallic, pearly, glassy, greasy, or silky

6. HARDNESS Hardness – finding out how easily a mineral can be scratched
They use a special chart called the Mohs Scale for Hardness
A greater number can scratch all minerals with a lower number

7. STREAK
streak – the color of the powder that a mineral leaves when it is scratched on a special plate
Always the same color even if the mineral differs

8. Layers of Rock
sediment – eroded materials that settles on land or on the bottom of lakes, rivers, and oceans
Some are smooth and round, others have sharp corners
New layers press on old ones
They harden and form sedimentary rocks

9. Types of Sedimentary Rocks
One type is made of materials that were once living things
Limestone is made of hard skeletons and shells of sea animals that lived long ago
Sandstone made up of bits of quartz that are the size of a grain of sand
Mudstone forms in lakes or oceans where tiny particles settle

10. How Rocks Change into Soil
Loose rocks at Earth’s surface and beneath it take a beating
Freezing water, plants roots, and Earth’s natural processes break apart the rock
These little pieces are ingredients in the soil
Soil is full of dead and decaying plant and animal remains too

11. How Rocks Tell a Story
sediment – eroded materials that settles on land or on the bottom of lakes, rivers, and oceans

13. How a Fossil Forms
sediment – eroded materials that settles on land or on the bottom of lakes, rivers, and

14. Igneous Rocks
sediment – eroded materials that settles on land or on the bottom of lakes, rivers, and

15. Metamorphic Rocks
sediment – eroded materials that settles on land or on the bottom of lakes, rivers, and

16. The Rock Cycle
sediment – eroded materials that settles on land or on the bottom of lakes, rivers, and