ROCK IDENTIFICATION LAB

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ROCK IDENTIFICATION LAB
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What type of rock is this? Where or how is it
formed?
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Obsidian

• Mafic (black) Extrusive Igneous Rock
• No crystals formed
• Glassy
• Very quick cooling molten rock (lava)

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What type of rock is this? Where or how is it
formed?
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Basalt

• Mafic Extrusive Igneous Rock
• Fine grained (some small crystals)
• Formed from dark dense lava
• Pyroxene, plagioclase feldspar

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What type of rock is this? Where or how is it
formed?
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Scoria

• Mafic Extrusive Igneous Rock
• No crystals formed
• Forms as a frothy crust on the top of a lava flow
  or as material ejected from a volcanic vent and
  solidifying while airborne
• Many holes formed - gasses released

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What type of rock is this? Where or how is it
formed?
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Pumice

• Felsic Extrusive Igneous Rock
• No crystals formed
• Quick cooling molten rock (lava)
• Many holes formed - gasses released
• Floats on water

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What type of rock is this? Where or how is it
formed?
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Granite

• Felsic Intrusive Igneous Rock
• Coarse Grained - can see crystals
• Contains quartz and feldspar

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What type of rock is this? Where or how is it
formed?
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Shale

• Clastic Sedimentary Rock
• Thin, dark gray sheets easily broken
• Formed from mud and clay being pressed together

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What type of rock is this? Where or how is it
formed?

• Image Source

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Sandstone

• Clastic Sedimentary Rock
• Light red/dark pink with very small pieces of
  sand
• Quartz cemented by silica or lime
• Most form in shallow seas

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What type of rock is this? Where or how is it
formed?

• Image Source

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Coal

• Organic Sedimentary Rock
• Black, smooth and lightweight
• Formed from layers of plant remains that are
  pressed together over time

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What type of rock is this? Where or how is it
formed?

• Image Source

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Limestone

• Organic Sedimentary Rock
• Calcium Carbonate - calcite
• Forms from the accumulation of shell, coral, and
  fecal debris in clear, warm, shallow marine waters

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What type of rock is this? Where or how is it
formed?
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Conglomerate

• Clastic Sedimentary Rock
• Red with rounded pebbles cemented together
• Formed near moving water

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• What type of rock is this? Where or how is it
  formed?

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Quartzite

• Metamorphic Rock
• Non-Foliated
• Individual quartz grains have recrystallized but
  are too small too see
• Metamorphism of Sandstone

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What type of rock is this? Where or how is it
formed?
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Marble

• Metamorphic
• Non-Foliated
• Made of mostly small to medium sized calcite
  crystals
• Metamorphism of Limestone

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What type of rock is this? Where or how is it
formed?
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Gneiss

• Metamorphic
• Foliated pink and grey alternating bands
• Medium to coarse grained texture
• Metamorphism of Granite

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What type of rock is this? Where or how is it
formed?
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Slate

• Metamorphic Rock
• Foliated
• Breaks into thin slices
• Metamorphism of Shale

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What type of rock is this? Where or how is it
formed?
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Hornfels

• Metamorphic Rock
• Non-foliated
• Fine grained crystals
• Metamorphism of clays or Shales

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Comparisons

• Basalt vs. Slate
• Both dark colors
• Basalt is igneous and Slate is metamorphic
• Pumice vs. Basalt
• Both igneous made of quick cooling lava
  (extrusive)
• Pumice is felsic and Basalt is mafic
• Granite vs. Gneiss
• Both have course grains/crystals
• Granite is igneous and Gneiss is metamorphic

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Comparisons

• Scoria vs. Pumice
• Both are porous (have air bubbles/holes)
• Scoria is mafic and Pumice is felsic
• Obsidian vs. Coal
• Both are black, no crystals
• Obsidian is igneous and Coal is sedimentary
• Marble vs. Limestone
• Both are made of calcite
• Marble is metamorphic and Limestone is sedimentary

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Comparisons

• Slate vs. Shale
• Both thin slices, made of mud and clay, dark
  color
• Slate is metamorphic (morphed from shale), Shale
  is sedimentary
• Hornfels vs. Slate
• Both metamorphic rocks made from Shale
• Hornfels is not foliated and Slate is foliated
• Sandstone vs. Quartzite
• Both grainy and made of Quartz
• Sandstone is sedimentary and Quartzite is
  metamorphic

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Comparisons

• Limestone vs. Marble
• Both are made of calcite
• Limestone is sedimentary and Marble is
  metamorphic
• Conglomerate vs. Limestone
• Both sedimentary rocks formed in or near water
• Conglomerate is clastic (made of pebbles cemented
  together by moving water) and Limestone is
  organic (made of shell coral, fecal debri found
  in shallow water)
• Gneiss vs. Granite
• Both contain course grain crystals
• Gneiss is metamorphic and Granite is igneous

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Comparisons

• Quartzite vs. Sandstone
• Both contain the mineral Quartz
• Quartzite is metamorphic (pressure and heat),
  Sandstone is sedimentary (cemented together by
  water sandstone or lime)
• Coal vs. Obsidian
• Both are black and smooth and contain no crystals
• Coal is sedimentary and Obsidian is igneous
• Shale vs. Slate
• Both made of mud and clay (Slate is made from
  Shale)
• Shale is sedimentary and Slate is metamorphic