Classifying Rocks

Classifying Rocks

• Are made of mixtures of minerals and other materials, although some may contain only a single mineral.– Granite• Quartz• Feldspar,• Mica• Hornblend

Rocks

• Size, shape and pattern of rock grains.– Grains- particles of minerals or other rocks.

Texture

• Coarse Grained- Large and easy to see.

• Fine Grained- small.

Texture (Grain Size)

• Grains vary widely.– Tiny particles of sand.– Look like seeds– Crystals– Smooth / rounded– Jagged

Texture (Grain Shape)

• Grains often form patterns.

– Some lie in flat layers.

– Rows of grains.

– Random grains.

Texture (Grain Pattern)

• Have no grain.– They cool very quickly

when they form, gives the rock a smooth, shiny texture like thick glass. (obsidian)

– Or made out of extremely small particles of silica that settle out of water. (flint)

Texture (No Visible Grain)

• 3 Groups- refers to how the rocks formed.

Origin

• Use a microscope to look at the size & shape of crystals to ID (identify) minerals in the rock.

• Acid test- tests for carbonates.

• Magnetic Test- tests for iron and nickel.

Mineral Composition

Rock Cycle