Chapter 14

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Chapter 14 The Rock Cycle

• Composition of Earths Crust
• 47 Oxygen
• 28 Silicon
• II. Minerals
• A. Properties
• 1. Inorganic
• 2. Naturally occurring
• 3. Solids
• 4. Definite chemical composition
• (elements or compounds)
• 5. Crystalline shape

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• B. Identification
• 1. Color (least reliable)
• same mineral/different colors (Quartz)
• can change color (oxidize)
• 2. Luster reflection of light
• Metallic
• Dull or Powdery
• Pearly
• Glassy

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• 3. Hardness resistance to scratching
• Mohs scale (1-10)
• fingernail scratches 1-2
• steel file scratches 3-5
• can scratch glass 6-9
• 4. Streak color of powder left when
• mineral is scratched on hard surface

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• 5. Density (Specific Gravity)
• Mass/Volume
• 6. Cleavage edge from breakage
• fracture no smooth side
• 1 plane cleavage thin layers
• 2 plane cleavage top bottom flat
• 3 plane cleavage cubic
• 7. Special Properties
• magnetic
• bubbles with acid
• salty taste

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• III. Rocks
• A. Igneous Rock
• cooled from moltan lava or magma
• 1. Intrusive (Plutonic)
• cool slowly, below surface
• have large visible crystals
• a. Felsic
• Aluminum/Silica
• Acidic, Light Color/Red
• Ex Granite
• b. Mafic
• Iron/Magnesium
• Basic, Dark Color/Green
• Ex Gabbro

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• 2. Extrusive (Volcanic)
• cool rapidly, above ground
• fine grained, may have pores
• a. Felsic examples
• Pumice frothy
• Rhyolite fine grained
• b. Mafic examples
• Obsidian glassy
• Scoria frothy
• Basalt fine grained

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• B. Sedimentary Rock
• made of weathered material
• may contain fossils
• 1. Clastic
• made of rock sand fragments
• Examples
• Breccia angled rock fragments
• Conglomerate cemented pebbles
• Sandstone cemented sand
• Shale clay or mud

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• 2. Nonclastic
• chemically formed
• Examples
• Limestone
• calcite from animal decomposition
• Chert quartz dissolved,
• then water evaporates

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• C. Metamorphic Rock
• Igneous or Sedimentary Rock
• changed by heat pressure
• 1. Foliated have parallel bands
• Examples
• Slate made from shale
• Gneiss made from granite
• Schist made from sandstone
• 2. Unfoliated none or sporadic bands
• Examples
• Marble made from limestone
• Quartzite made from sandstone

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• IV. The Rock Cycle
• Sedimentary
• Metamorphic Igneous
• Magma

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• Quiz Next Week
• Match Minerals with their properties
• Name classes of Igneous, Sedimentary,
• Metamorphic Rocks give examples