3. ROCK FORMING MINERALS
ABOUT 20 minerals make – up most of the rocks in the Earth’s crust.

4. In 3 CATEGORIES COLOR TEXTURE Look & feel of a rock
HOW GEOLOGIST CLASSIFY ROCKS
In 3 CATEGORIES
MINERAL COMPOSITION
COLOR
TEXTURE
Look & feel of a rock
The mixture of minerals & other materials that make a rock
Gives clues about what minerals are in the rock
Grain size
Grain shape
Grain Pattern

5. MINERAL COMPOSITION

6. COLOR

7. GRAIN SIZE GRAIN SHAPE GRAIN PATTERN
The size of the mineral visible in the rock
Course Grain:Granite
Fine Grained: Basalt
GRAIN SHAPE
The shape of the mineral visible in the rock
Jagged: Breccia
Rounded: Conglomerate
GRAIN PATTERN
The design of the mineral visible in the rock
Banded
Non - Banded

8. ORIGIN