Transcript Classifying Rocks

Classifying
Rocks
CH 3 Prentice Hall
p. 74-77
Rocks
• Are made of mixtures of minerals and other
materials, although some may contain only a
single mineral.
– Granite
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Quartz
Feldspar,
Mica
Hornblend
Characteristics (brainstorm)
Group A
Group B
Rock Color Texture
Group C
Luster
Group D
Group E
Group F
Density
Hardness
Porous
Texture
• Size, shape and pattern of rock grains.
– Grains- particles of minerals or other rocks.
Texture (Grain Size)
• Course Grained- Large and easy to see.
• Fine Grained- small.
Texture (Grain Shape)
• Grains vary widely.
– Tiny particles of sand.
– Look like seeds
– Crystals
– Smooth / rounded
– Jagged
Texture (Grain Pattern)
• Grains often form patterns.
– Some lie in flat layers.
– Rows of grains.
– Random grains.
Texture (No Visible Grain)
• Have no grain.
– They cool very quickly
when they form, gives the
rock a smooth, shiny
texture like thick glass.
(obsidian)
– Or made out of extremely
small particles of silica that
settle out of water. (flint)
Origin
• 3 Groups- refers to how the rocks formed.
Igneous
Sedimentary
Metamorphic
• Forms from
cooling
molten rock.
• Magmabelow the
surface.
• Lava- above
the surface.
• Forms from
particles of
other rocks,
remains of
plants and
animals that
are pressed
and cemented
together.
• Forms from
pre-existing
rock, deep
underground.
• Changes rock
with heat,
pressure and
chemical
reactions.
Mineral Composition
• Use a microscope to look at the size & shape
of crystals to ID (identify) minerals in the
rock.
• Acid test- tests for carbonates.
• Magnetic Test- tests for iron and nickel.
Rock Cycle