Ch. 5 Sec. 1

Classifying Rocks

YouTube video-Bill Nye Rocks Rock Harder Song

Discover Activity-How do rocks compare? Pg. 144

Marble Shale Color Texture Which is harder?Which is denser?

rockmade of mixtures of minerals and other materials

geologists observe rock’s

1. mineral

composition

2. color

3. 3. texturetexture

1. mineral composition

•made of mixtures of minerals & other materials

rock-forming minerals

• about 20 minerals make up most of rocks of crust

2. color•gives clues to rock’s mineral composition

Granite is usually a light colored rock that has a high silica content.

Basalt is usually a dark colored rock that has a low silica content.

3. texture3. texture•Look & feel of a Look & feel of a rock’s surfacerock’s surface

3 Different Rocks

How are these rocks different from oneanother?

How are they similar?

grains•particles of minerals or other rocks

•gives rock its texture

grain shape• ex:

exploding stars crystal shapes rock fragments- smooth, rounded or jagged

conglomerate

Weathering Affects Grain Shape

grain pattern

• flat layers

• random

• banded

• nonbandedquartzite

Layered or random grains ?Layered grains

Nonbanded or banded grain patternbanded grain pattern

grain size• coarse grained= large & easy to see

• fine grained= grains so small- need microscope

• some have no visible grain

Diorite is _______ grained.

coarse

Types of Rock video clip

Make model of granite

Name that rock activity