Identifying Rocks

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Identifying Rocks
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• All rocks are classified by how they form.
• Rocks can form a couple of different ways
• Intense heat and pressure
• Cooling
• Recycling of old rock inside the Earth
• Erosion and compaction of sediment over millions
  of years
• Based on how rocks form, there are 3 types
• Igneous
• Metamorphic
• Sedimentary

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Igneous

• Are formed when lava cools on the Earths surface
  OR when magma cools down below the Earths
  surface
• Hints that you are seeing an igneous rock
• Bubbles
• Glassy appearance
• Big grains of minerals

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Bubbles
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Glassy Appearance
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Big Grains
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Metamorphic

• Metamorphic rocks are made when old rocks change
  due to heat or pressure inside of the Earth
• Hints that you are seeing a metamorphic rock
• Bending layers
• Squished Grains

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Bending Layers
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Squished Grains
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Sedimentary

• Sedimentary rocks are made of sediments
  (particles) that build up in layers, usually at
  the bottom of a river or lake.
• Hints that you are seeing a sedimentary rock
• Flat layers
• Mix of particle size

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Flat Layers
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Mix of Particle Size
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Test Yourselfby trying to identify the correct
type of rock for each of the following pictures
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Sample 1
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Sample 2
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Sample 3
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Answers

• Sedimentary (mix of particle size)
• Igneous (bubbles)
• Metamorphic (bending layers)
• How did you do???