PSNB+5.1

toc =Classifying Rocks (pg 136)=

Vocabulary

 * texture:** the way a rock looks and feels
 * grains:** the small pieces of minerals or other rocks a rock is made up of
 * igneous rock:** a rock that's created from the cooling of magma or lava
 * sedimentary rock:** a rock that forms when pieces of other rocks/plants+animals are pushed together
 * metamorphic rock:** a type of rock formed when an earlier rock is changed by natural forces.

How Geologists Classify Rocks

 * Rocks make up many parts of earth's crust
 * Mountains, hills, valleys, beaches, etc...
 * Geologists study/ collect samples of rock to classify them
 * There are different ways you classify rocks in the mountains
 * Camera/notebook to record information
 * Use chisel to remove samples to study
 * Rock samples- geologists study color, texture, and chemical composition

Texture
Grain Size Grain Shapes Grain Pattern No Visible Grain
 * Minerals need more than color to classify
 * Texture is another way
 * Rocks/grains give texture
 * Geologists use different terms to classify texture
 * Number of terms, like size, shape pattern, etc...
 * Some grains are large and easy to see
 * Some grains are small and need microscopes
 * Differences in fine-grained, and coarse-grained
 * Vary in shape
 * Some rocks shape in crystals, that form rocks
 * Differences in shape
 * Grains in rock usually form patterns
 * Lots of different patterns
 * Contrast, random, etc...
 * Some have no grain
 * When some form, cool quickly
 * Some have no crystals
 * Some rocks have visible grain, some don't

Mineral Composition

 * Some geologists use tests
 * On rocks, surface, or compounds

Origin

 * Three major groups- Igneous, metamorphic, sedimentary
 * Igneous- cooling of molten rock
 * Metamorphic- Rock is changed by heat, pressure, of chemical reaction
 * Sedimentary- Particles joined together



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