Transcript here - Jarod M. Lambert

Rocks and Minerals
Chapters 10 & 11
Rocks and Minerals • Science, 8th Grade
Rocks
• Earth’s crust is made of rock.
• Rocks are mixtures of minerals and sometimes
other materials.
background image source: http://veimages.gsfc.nasa.gov/7100/world.topo.bathy.200401.3x5400x2700.jpg
Rocks and Minerals • Science, 8th Grade
Studying Rocks
• When studying a rock sample, geologists
observe the rock’s:
– Color
• click here for a rock color chart
– Texture
– Chemical Composition
Rocks and Minerals • Science, 8th Grade
Color Chart Quiz
image source:
http://geology.about.com/library/bl/images/blgneiss.htm
Click the color on the color
chart that best identifies the
color of the rock above.
Rocks and Minerals • Science, 8th Grade
That is not correct…
• Please click on the “Back” button and try again.
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Rocks and Minerals • Science, 8th Grade
Excellent!
• You have correctly identified the rock on the color chart.
Click on the “Next” button to continue.
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Rocks and Minerals • Science, 8th Grade
Texture
• Most rocks are made up of grains, particles or
minerals, or other rocks.
• Texture is the look that results from:
– Size
– Shape
– Pattern of rock’s grains
Rocks and Minerals • Science, 8th Grade
Grains
• Coarse-grained: large/easy to see
• Fine-grained: small, even microscopic
– Click here for rock identification tables that include
information on grain size.
Obsidian – A Fine-grained Rock
image source: http://geology.about.com/library/bl/images/blobsidian.htm
Sandstone – A Coarse-grained Rock
image source: http://geology.about.com/library/bl/images/blsandstone.htm
Rocks and Minerals • Science, 8th Grade
Grain Pattern
• Grains in rock often form a pattern.
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Flat layers (strata)
Wavy, swirling patterns
Rows of beads
Random or no pattern
Example
Example
Example
Example
Rocks and Minerals • Science, 8th Grade
Flat Layers (strata)
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Rocks and Minerals • Science, 8th Grade
Wavy, Swirling Patterns
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Rocks and Minerals • Science, 8th Grade
Rows of Beads
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Rocks and Minerals • Science, 8th Grade
Random or No Pattern
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Rocks and Minerals • Science, 8th Grade
Quick Forming Rocks
• Some rocks have no grain because they cooled
too quickly when they formed.
Rocks and Minerals • Science, 8th Grade
Rock Groups
• There are three groups of rocks:
– Igneous
– Metamorphic
– Sedimentary
• Click on the links above to find the definition of each group of rock. Once
you have reviewed these definitions online, click on the arrow to continue.
Rocks and Minerals • Science, 8th Grade
Igneous Rocks
• Formed from the cooling of molten, or melted,
rock
Pumice
Granite
Basalt
Rocks and Minerals • Science, 8th Grade
Metamorphic Rocks
• Formed when existing rock is changed by heat,
pressure, or chemical reactions
Gneiss
Schist
Phyllite
Rocks and Minerals • Science, 8th Grade
Sedimentary Rocks
• Formed when particles of other rocks, plants,
or animals are cemented together
Sandstone
Breccia
Siltstone
Rocks and Minerals • Science, 8th Grade
The Rock Cycle
Click here for another illustration of the rock cycle.
Rocks and Minerals • Science, 8th Grade
Online Rock Cycle Activities
• The Rock Cycle
– Click on the image below to access online resources
and activities.
Rocks and Minerals • Science, 8th Grade
Rocks and Minerals • Science, 8th Grade
Minerals
• A mineral:
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Occurs naturally
Is inorganic
Is Solid
Has a crystal structure
Has a definite chemical composition
Rocks and Minerals • Science, 8th Grade
Minerals
• There are three thousand (3000) minerals.
• One hundred (100) minerals are common.
• Twenty (20) minerals make up most of the
rocks of Earth’s crust (rock-forming minerals).
Rocks and Minerals • Science, 8th Grade
Mineral Formation
• Minerals form through:
– Crystallization of melted materials.
– Crystallization of materials dissolved in water.
Rocks and Minerals • Science, 8th Grade
Crystals
• Repeating patterns of a
mineral’s particles that
form a solid.
– Click here for a crystal
experiment from
National Geographic.
Rocks and Minerals • Science, 8th Grade
Mineral Composition
• All minerals contain certain elements in definite
amounts.
• Most minerals are compounds (two or more
elements).
• Silver and gold are considered minerals.
Rocks and Minerals • Science, 8th Grade
Mohs Hardness Scale
• The Mohs Hardness Scale ranks ten minerals
from softest to hardest.
source: http://www.amfed.org/t_mohs.htm
Rocks and Minerals • Science, 8th Grade
Ranking Minerals
• Minerals are ranked according to:
• Click on the word below for more information.
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Color
Streak
Luster
Density
Cleavage
Fracture
Rocks and Minerals • Science, 8th Grade
Color
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Rocks and Minerals • Science, 8th Grade
Streak
• Streak is the color of a mineral’s powder.
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Rocks and Minerals • Science, 8th Grade
Luster
• Luster is how shiny a mineral is.
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Rocks and Minerals • Science, 8th Grade
Density
• Density is mass per unit volume (specific
gravity).
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Rocks and Minerals • Science, 8th Grade
Cleavage
• Cleavage is the breaking
of a mineral along a
regular line.
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Rocks and Minerals • Science, 8th Grade
Fracture
• Fracture is the irregular breaking of a mineral.
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Rocks and Minerals • Science, 8th Grade
Fluorescence
• Fluorescence refers to minerals that glow under
ultraviolet light.
Rocks and Minerals • Science, 8th Grade
Magnetism
• Magnetism occurs naturally in some minerals,
such as magnetite.
Rocks and Minerals • Science, 8th Grade
The End
• Click here for another online resource about
rocks and minerals.
• Click the arrow below to return to the beginning
of this presentation.
Rocks and Minerals • Science, 8th Grade