1. Classifying Rocks Section 4-1
7th grade Science

2. Classifying Rocks
When studying rocks, scientists observe the rock’s mineral composition, color, and texture

3. Classifying Rocks
Rock Forming Minerals 20 of the minerals that make up a majority of the earths rocks

4. Classifying Rocks
Granite a light colored rock with a high silica content
Basalt a dark colored rock with a low silica content

5. Classifying Rocks-Texture
Grains particles in rocks that give rock its texture
Grain size- fine or coarse
Grain shape- round or jagged
Grain pattern- Banded or nonbanded

6. Classifying Rocks- How rocks Form
There are 3 major groups of rocks

7. Classifying Rocks- How rocks Form
Igneous Rock made from cooling Magma or Lava

8. Classifying Rocks- How rocks Form
Sedimentary Rock  Forms when particals of other rocks and/or remains of plants and animals are pressed and cemented together
Forms layers

9. Classifying Rocks- How rocks Form
Metamorphic rock  formed or changed by heat and pressure or chemical reactions. Most forms deep underground