Name: _______________________________________ Date: ______________
Chapter 8 How Earth Changes Over Time
Lesson 6 “The Rock Cycle”
What Are the Properties of Rocks? (p. D70-D71)
Rocks Are Made of Minerals
 Rocks make up the Earth’s____crust_____. Many rocks are made of
____minerals______.
 A mineral is a naturally occurring solid with a definite ___structure_____,
and each mineral is made up of particular _____elements_______.
 A rock can be one mineral or a ____mixture_____ of minerals.
 You can tell minerals apart by their structure and ____properties______.
o Hardness is a measure of how easily a mineral can be
____scratched__.
o Luster describes how a mineral reflects ___light____. A
mineral may shine like metal or be dull, silky, or glassy.
o Streak describes a mineral’s __color____ when it is ground into
a powder.
o Cleavage is the way that a mineral _____breaks____ which can be
smooth or jagged.
o Color describes a mineral’s _______surface______ color.
o Density measures the amount of mass within a given space, and
is compared to ___water_____in the case of minerals.
 Most rocks are a mixture of ____minerals_____ and can be identified by
the minerals they contain.
 Another way to tell rocks apart is by their ____texture______(coarse or
glassy), and/or their _____structure________ (the way the pieces fit
together).
 A rock gets its properties from the way it forms, which is classified into
____three_____ main groups.
What Are Igneous Rocks? (p. D72-D73)
 Igneous rocks form when ___hot____ ____liquid_____ rock
material cools and hardens into solid.
 Some igneous rocks form from ___magma____, below the Earth’s surface.
 Magma becomes trapped as it ___pushes_____ its way to the surface and
___cools____ slowly over many centuries.
 As it cools, igneous rocks form large _____crystals____ which give the
rocks a coarse texture.
 Igneous rocks that form underground are called ___intrusive____ rocks.
 When magma reaches the surface of the Earth before it cools, it may flow
from a _____volcano_____ as lava.
 At the surface, ___lava_____ is exposed to cooler temperatures and
__hardens_____ quickly, with no time for large ____crystals____ to form.
 These rocks have a fine ____texture_____ and some may even look like
solid ___glass___ .
 Igneous rocks that form above ground are called ____extrusive____rocks
Name: ________________________________________ Date: _____________
Chapter 8 How Earth Changes Over Time
Lesson 6 “The Rock Cycle”
What is Sedimentary Rock? (p. D74-D75)

Sedimentary rock is made from bits and pieces of ____weathered____
rocks that have been ___eroded_____, and deposited in a new location.
 Layers of sediment build up and ___press____ on the layers below
causing the fine particles to ___squeeze____ together and harden into
solid rock.
 Larger pieces of sediment become stuck, or ___cemented_____ together,
as ___dissolved______ minerals form a kind of glue that holds the
sediment together.
 Sedimentary rocks can also form when mineral crystals are left behind,
as the water that they were dissolved in,__dries___ __up___.
 Some sedimentary rocks are made from sediment that was once part of
____living_____ ___things_____, such as the shells of ocean
animals. The fragments of ____shells___ pile up into layers that
become solid rock.
What Are Metamorphic Rocks? (p. D76-D77)
 The word metamorphic means “___change_____.”
 A metamorphic rock was once another kind of rock, such as an
___igneous_____, ___sedimentary_____ or even another
metamorphic rock, that “changed.”
 They become rocks with different properties through great ____heat___,
great __pressure____, and sometimes through chemical reactions.
 Metamorphic rocks often form deep underground, where the
____temperature_____ are high and the __pressure____ is great from
the rocks above.
o Parts of the Earth’s crust are exposed to great heat and pressure,
such as where the ____boundaries____of the plates collide, forcing
rock deep ______underground_______ .
o Metamorphic rock is also formed when rocks come into contact with
magma as it ___pushes___ through or against rock, changing
the ____properties________ of the surrounding rock.
o When metamorphic rock forms, it does not ___melt_____ , but
instead changes occur in the ____structure______ and
____texture____ of the rock.
Granite -
great heat and pressure changes it to - Gneiss