ROCKS

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ROCKS
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ROCKS

• 1. Rock A solid mixture of minerals and other
  materials makes up the Earths crust

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• 2. How to Study Rock Samples Observe color,
  texture, and determine mineral composition

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• 3. Rock-Forming Minerals About 20 minerals that
  make up most of the rocks of Earths crust (ex
  quartz, feldspar, hornblend, mica)

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ROCKS

• 4. Texture The look and feel of the rocks
  surface (smooth glassy, rough chalky)

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• 5. Grains Particles of minerals or rocks which
  make up a rock and give the rock its texture

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• 6. Grain Size -
• A) Coarse-Grained Grains in the rock are easy
  to see (granite)
• B) Fine-Grained Grains are so small that they
  can only be seen with a microscope (slate)
• C) No Visible Grain Rock cools so quickly when
  it forms, that there are no grains visible (flint)

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• 7. Grain Shape
• A) Rounded Grain Smooth (conglomerate)
• B) Jagged Grain Not smooth (breccia)

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• 8. Grain Pattern
• A) Non-Banded Grains do not lay in bands
  (quartzite)
• B) Banded Grains lay in bands (gneiss)

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• 9. Origin of Rocks Igneous, Sedimentary,
  Metamorphic

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• A) Igneous Rocks Forms from the cooling of
  magma or lava (granite, basalt, obsidian, pumice)

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• B) Sedimentary Rocks Forms when particles of
  other rocks or the remains of plants and animals
  are pressed and cemented together (limestone,
  sandstone)

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• C) Metamorphic Rocks Forms when an existing
  rock is changed by heat, pressure, or chemical
  reactions (marble, gneiss, quartzite)