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ROCK CYCLE UNIT REVIEW
By Mrs. Susan Dennison
2012-13
What are minerals?
A mineral is a solid material, formed in
nature, with particles arranged in a repeating
pattern (crystals).
How do minerals form?
Minerals form in many ways: in the mantle,
at or near the surface, and from mineral-rich
water.
Calcite is a mineral found in
chalk. It can form near the
Earth’s surface or in the
ocean, when calcium, oxygen,
and carbon combine in sea
water. Some sea animals form
calcite shells. Calcite also
forms as water evaporates in
limestone caves.
What are the properties of minerals?
Mineral properties include: streak, luster, and
hardness. Minerals can be tested for these.
Why are diamonds so hard?
Diamonds are hard because the particles
they are made of are bound together so
tightly. They are formed in the lower
crust/upper mantle where pressures and
temperatures are extremely high. They will
scratch all other minerals and can cut glass!
Diamond mine in Siberia
Rough diamond
Polished, cut diamonds
How do we use minerals?
We eat and drink minerals, wear them as
jewelry and makeup, build things with them,
clean with them, and more!
What are gemstones?
Of the more than 3,000 minerals, about 100
are considered so beautiful and rare that they
are called gemstones.
What are rocks?
Rocks are materials made from one or more
minerals. Earth is made of mostly rocks.
What are the 3 types of rocks?
All rocks can be classified into three groups
based on how they were formed.
1. IGNEOUS
2. SEDIMENTARY
3. METAMORPHIC
No, NOT this type of rock!
How are igneous rocks formed?
Igneous rocks form when melted rock
hardens. Rocks formed from lava are finegrained and rocks formed from magma are
course-grained. Basalt is the most common
igneous rock formed at Earth’s surface.
What is a common igneous rock used
in construction?
Granite is a strong igneous rock often used for
building. It is made from large grains of quartz,
feldspar, and mica minerals joined together
tightly.
What does “igneous” mean?
The word igneous comes from the Latin word
ignis, which means “fire.” Think about why.
How are sedimentary rocks formed?
Sedimentary rocks are formed when, over a long
time, layers of sediment weathered away and
deposited are squeezed (compressed) and stuck
together (hardened) in layers.
What are some types of sedimentary
rocks we commonly see?
Conglomerate, sandstone, shale, and limestone are
commonly seen sedimentary rocks.
How are metamorphic rocks formed?
Metamorphic rocks are made of igneous and
sedimentary rocks that have been changed by high
heat and pressure. Even the minerals that make up
the rocks are changed!
It's not hard to see that this metamorphic
rock, called gneiss, has been intensely
folded! This rock had to have been under
very high pressure and temperature to
allow it to fold like this without breaking.
Photo by Edward P. Klimasauskas
What does metamorphic mean?
The word metamorphic is made of two word
parts, meta means “change,” and morphic
means “form.” Think about why.
What is the rock cycle?
The rock cycle is a description of the
processes that change the solid Earth.
What are the processes involved in
the rock cycle?
We have studied many of these in our previous
geology unit!
1.
2.
3.
4.
5.
6.
7.
Weathering
Erosion
Heat
Pressure
Melting
Compaction
Cementation
What is a good model to describe
Earth’s rock cycle processes?
Bread can be used to model the rock cycle!
A loaf of bread is new, solid
material formed after heating
and cooling. It is like igneous
rock.
Bread crumbs are “eroded”
Pieces, or sediments. They can be
layered in a pan, and squeezed
together, like sedimentary rock.
A piece of toast has been changed
by heat. It is like metamorphic
rock!