Classifying Rocks CH 3 Prentice Hall p. 74-77

Rocks Are made of mixtures of minerals and other materials, although some may contain only a single mineral. Granite Quartz Feldspar, Mica Hornblend 2

Characteristics (brainstorm) Group A Group B Group C Rock Color Texture Luster Group D Group E Group F Density Hardness Porous

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

Texture (Grain Size) Course Grained- Large and easy to see. Fine Grained- small. 5

Texture (Grain Shape) Grains vary widely. Tiny particles of sand. Look like seeds Crystals Smooth / rounded Jagged 6

Texture (Grain Pattern) Grains often form patterns. Some lie in flat layers. Rows of grains. Random grains. 7

Texture (No Visible Grain) 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) 8

Origin 3 Groups- refers to how the rocks formed. Igneous Forms from cooling molten rock. Magma- below the surface. Lava- above the surface. Sedimentary Forms from particles of other rocks, remains of plants and animals that are pressed and cemented together. Metamorphic Forms from pre-existing rock, deep underground. Changes rock with heat, pressure and chemical reactions.

Mineral Composition 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.

Rock Cycle Igneous Sedimentary Pressure Metamorphic Molten Material