1. Rocks

2. rocks
These rocks are at the bottom of the Grand Canyon and are very old. They have certain characteristics that allow geologists to identify exactly what type of rock they are. All rocks do not look the same. Geologists use the different characteristics of rocks to categorize the different rock types on Earth.

3. What is a rock?
A geologist can tell how a rock was formed just by looking at it!! Rock: A naturally occurring solid mixture composed of minerals, smaller rock fragments, organic matter or glass. Grains: The individual particles in a rock.

4. What is a rock?
These two rocks mostly contain quartz. They look different because they formed in different ways.
Both rocks are made of mineral grains.
The arrangement of the grains give clues to how the rocks formed.

5. Classifying rocks
Three major types of rocks:
Igneous Metamorphic Sedimentary

6. Classifying Rocks: Igneous Rocks
Igneous Rocks: Most abundant rocks on Earth.
Most form deep below Earth’s surface
All form in a similar way
Formation of Igneous Rocks
As magma or lava cools, mineral crystals begin to form, which are the grains of new igneous rock.
Magma: Molten rock inside Earth.
Lava: Molten rock that erupts onto Earth’s surface (outside Earth).

7. Classifying Rocks: Igneous rock
Igneous Rock **Magma is the source for Igneous rocks. Texture and Composition are used to classify Igneous rocks. Minerals from magma and lava form the grains of a new igneous rock. Texture: Grain size and how the grains are arranged in rocks.

8. Classifying Rocks: Igneous Rocks
Lava at Earth’s surface cools quickly, so crystals do NOT have much time to grow in size. Geologist describe the texture of igneous rocks with small crystals as fine-grained.

9. Classifying Rocks: Igneous Rocks
Deep below Earth’s surface, magma cools slowly, the crystals have more time to grow. Geologist describe the texture of igneous rocks with large crystals as coarse-grained.

10. Classifying Rocks: Sedimentary Rocks
Sediment: Rock and mineral fragments that are loose or suspended in water. **Sediments is the source material for Sedimentary Rock Formation of Sedimentary Rocks Lithification: The process through which sediment turns into rock.

11. Classifying Rocks: metamorphic Rocks
Extreme high temperatures and pressure can cause change in rocks. Parent Rock: Original rock New rock formed is called Metamorphic Rock Metamorphic Rocks: Form when parent rocks are squeezed, heated, or exposed to hot fluids.

12. Classifying Rocks: metamorphic Rocks
The parent rock DOES NOT melt – they remain solid – texture and, sometimes, mineral composition of the parent rock change.
Two main textures of Metamorphic Rocks:
Foliated Metamorphic Rock
Nonfoliated Metamorphic Rock

13. Classifying Rocks: metamorphic Rocks
Foliation: Uneven pressures causing flat minerals to line up, giving the rock a layered appearance. Nonfoliation: Rocks do not have a layered texture. ** Foliation is the most obvious characteristic of metamorphic rocks**

14. Rocks in Everyday Life
Rocks are abundant natural resources that are used in many ways based on their physical characteristics. Some Igneous rocks are hard and durable... Ex. Granite – Some Igneous rocks is soft but contain small pieces of hard glass, which makes it useful for polishing and cleaning… Ex. Pumice.

15. Rocks in Everyday Life
Natural layering makes sedimentary rock a high- quality building stone. Ex. Sandstone and limestone are used in buildings. Limestone is also used in cement.

16. Rocks in Everyday Life