Chapter 4
Rocks: Mineral Mixtures
Standard S6E5.b
Investigate the composition of rocks in
terms of minerals
Section 1 pp.90, 95, 96
EQ: How are rocks and minerals
different?
• Rock
• Naturally occurring
solid mixture of one or
more minerals and
organic (living) matter
EQ: How are rocks classified?
• 3 Classes of Rocks
1. Igneous
2. Sedimentary
3. Metamorphic
Rocks are classified by:
• Composition
• The chemical makeup of
the rock –the minerals
and other materials
• Texture
• The size, shape and
positions of the rock
grains
• Provides clues as to how
and where the rock is
formed
Summary
• Write a paragraph that:
• Compares and contrasts minerals and
rocks.
• Write another paragraph that:
• Compares and contrasts composition and
texture.
Section 2 pp.98 – 101
EQ: Where do igneous rocks come
from?
• Igneous Rocks
• Igneous means “fire”
• Begins as magma
that contains many
minerals
• Cooled magma
hardens and solidifies
• Composition of
Igneous Rocks
• Determined by
minerals
• Light colored ones –
less dense– made of
aluminum, silicon
• Dark colored ones –
more dense, made of
iron, calcium, &
magnesium
• Texture of Igneous Rocks
• Size of the grains
• Fast cooling lava on the
surface of the volcano -fine grains or no
grains Ex: pumice
• Slow cooling magma
inside the Earth -large grains
Ex: granite
• Igneous Rock
Formation
• Intrussive igneous
rock -forms inside Earth
cools slowly
large grains
Ex: granite
• Igneous Rock
Formation
• Extrussive Igneous
Rock -forms on Earth’s
surface
cools fast
fine grains or no
grains
Ex: pumice
• Igneous Rock
Formation
• In other words, the
faster the magma or
lava cools the smaller
the grains of the rock
• The slower the
magma or lava cools
the larger the grains
of the rock
Summary
• Compare and contrast Stone Mountain’s
granite and pumice from a volcano.
Draw a Picture of the Formation of
Igneous Rocks
• Label intrusive, extrusive, magma, lava.
• Show the grain size of the developing
rocks.
• Indicate how fast the rocks cool.
• Name rock samples for each class of
igneous rocks.
Section 3 pp. 102 – 105
EQ: What are sedimentary rocks
made of?
• Sediment
• Fragments of
weathered rock &
minerals
• Strata
• Layers of sed. rock on
Earth’s surface that
forms when the sed is
deposited &
cemented together by
dissolved clacite &
quartz
• Stratification
• Process in which sed.
Rocks are arranged in
layers
EQ: What are the 3 classes of
sedimentary rock?
• Clastic
• Made of rock
fragments cemented
together by dissolved
calcite & quartz
• May be any grain size
• Examples:
conglomerate, shale,
sandstone
• Chemical
• From solutions of
dissolved minerals in
water
• The dissolved
minerals crystallize
• Ex: halite—salt—
NaCl Result of
supersaturated salt
water
• Organic
• Made from the remains of
dead organisms
• Ex: Chalk is made of tiny
sea creatures
• Ex: Coal forms
underground when
decomposed plant
material is changed into
coal by heat & pressure
Fossil fuels are nonrenewable resources
Summary
• Describe the formation of the 3 classes of
sedimentary rock.
• Draw a picture of how each sed. rock
forms
• Show the rock “before” it became a sed.
rock and the “after” or the resulting sed.
rock.
• Label each class of sedimentary rock.
• Compare and Contrast Igneous and
Sedimentary Rocks
Section 4 pp. 106 – 111
EQ: What is metamorphism?
• Metamorphism
• Change shape
• Metamorphic Rock
• The structure, texture
or composition of the
rock changes
because of extreme
heat and/or pressure
• A chemical change
occurs
• Deformation
• Change in the shape
of a rock caused by a
force, like squeeze or
stretch
EQ: What are the 2 classes of
metamorphic rock?
• Foliated
• Mineral grains are
arranged in bands
• Ex: mica, slate
• Non-foliated
• Random arrangement
of grains
• Ex: marble
Summary
• If I needed to make a tool from a rock,
should I choose a foliated or a non-foliated
metamorphic rock? Explain your answer.