1. Warm-Up: Mon 4/7 Write What You Know!
Write everything you know about the prompt below for five minutes, try for at least 3-4 complete sentences.
What can color tell you about a rock?

2. 4/10/2014 Rock Notes Major Key Term Key Term definition in own words
facts
pictures
Key Term

3. Classifying Rocks
Geologists classify rocks by composition, color, and texture
You have to break open a rock and look inside, as weathering can change the outside of a rock

4. Composition
Composition: what minerals, or other substances, is the rock made of?
Some rocks are made of only one mineral
Some rocks are a mixture of several minerals and other substances

5. Color A rock’s color provides clues to its mineral composition.
Granite – light colored, high in silica
Basalt – dark colored, low in silica
Color is not enough, many rocks have similar colors but different compositions

6. Texture Rocks are made of particles of minerals, called grains
Texture is the look and feel of a rock, determined by the grains inside, we study

7. Texture Grain Size Fine-grained: very small grains
Coarse-grained: very large grains

8. Texture
Grain Shape
Can be shaped by crystal shapes or by broken fragments of rocks or minerals
Can be smooth and rounded or sharp and jagged

9. Texture
Grain Pattern
The grains in a rock can form many different patterns
Flat layers, swirling lines, bands, different colors, randomly spaced grains

10. How Rocks Form