Download Chapter Introduction Lesson 1 What is a mineral? Lesson 2 How are

Chapter Introduction
Lesson 1 What is
a mineral?
Lesson 2 How are
minerals
identified?
Lesson 3 Sources and
Uses of Minerals
Chapter Wrap-Up
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Chapter Menu
What is a mineral?
•  A mineral is a naturally occurring,
inorganic solid with a definite chemical
composition and an orderly
arrangement of atoms or ions.
•  There are approximately 4,000
minerals on Earth, but only about 30
are common.
Lesson 1-1
What is a mineral? (cont.)
•  Of the 30 common minerals, ten are
rock-forming minerals, including quartz,
feldspar, and olivine.
•  These minerals occur naturally and are
not made in a laboratory.
Lesson 1-1
What is a mineral? (cont.)
•  Minerals have a definite chemical
composition.
•  Some minerals, such as silver and
sulfur, are composed of just one
element. These are known as native
elements.
•  Other minerals are made up of a
combination of several elements.
Lesson 1-1
What is a mineral? (cont.)
•  Minerals form predictable crystal
patterns.
•  The internal arrangement of atoms or
ions determines the shape of a crystal.
Lesson 1-1
What is a mineral? (cont.)
A crystal is a solid with a repeating
arrangement of atoms or ions in 3
directions.
Lesson 1-1
What is a mineral? (cont.)
•  Minerals are solids, meaning they
exhibit an orderly internal arrangement
of atoms or ions.
•  Minerals are inorganic, or not from
biologic origins.
•  Despite being inorganic, some
minerals can form as a result of
organic processes.
Lesson 1-1
The Structure of Minerals
•  Minerals occur in many different
shapes.
•  When a crystal forms under the right
conditions and has time to grow, it will
develop a characteristic crystal shape.
•  Most of the time, minerals grow in tiny
clusters.
Lesson 1-2
The Structure of Minerals (cont.)
•  The common rock-forming minerals are
composed of combinations of elements
that are abundant in Earth’s crust.
•  Oxygen and silicon are the two most
abundant elements in the crust.
Lesson 1-2
The Structure of Minerals (cont.)
•  The two main families of rock-forming
minerals are the silicates and the
nonsilicates.
•  A silicate is a member of the mineral
group that has silicon and oxygen in its
crystal structure.
•  Nonsilicate minerals do not contain
silicon.
Lesson 1-2
How do minerals form?
•  All minerals form through crystallization.
•  The process of crystallization occurs
when particles dissolved in a liquid or a
melt solidify and form crystals.
•  The chemical and physical properties of
minerals can help geologists infer the
type of environment where these minerals
formed.
Lesson 1-3
How do minerals form? (cont.)
•  Minerals can crystallize from either hot
or cool solutions.
•  As water evaporates from a cool
solution in a dry environment, solids
crystallize out of the water and form
minerals.
•  Sometimes minerals can crystallize
from water in environments that aren’t
dry.
Lesson 1-3
How do minerals form? (cont.)
•  Hot solutions are made when water
flows through cracks in the crust into
deep and hot environments.
•  Sometimes hot solutions carry large
concentrations of dissolved solids that
eventually become valuable mineral
deposits.
Lesson 1-3
How do minerals form? (cont.)
•  Minerals can also form from magma.
Magma is molten material stored
beneath Earth’s surface.
•  When magma erupts on or near Earth’s
surface, it is called lava or ash.
Lesson 1-3
How do minerals form? (cont.)
•  As lava or ash cools above ground or
magma cools underground, atoms and
ions arrange themselves and form
mineral crystals.
•  Small crystals form as lava cools
quickly on or near Earth’s surface and
large crystals sometimes form as
magma cools and crystallizes slowly
below Earth’s surface.
Lesson 1-3
How do minerals form? (cont.)
•  Minerals that form deep within Earth’s
crust and mantle are stable under high
pressure and high temperature
conditions.
•  Metamorphic activity can uplift minerals
from great depths onto Earth’s surface.
•  Changes in pressure and temperature
on Earth’s surface combined with agents
of erosion can cause minerals to break
down and eventually form new minerals.
Lesson 1-3
Physical Properties
•  Mineralogists are scientists who study
the distribution of minerals, mineral
properties, and their uses.
•  Scientists use the physical and
chemical properties of minerals to learn
a mineral’s identity and classify
unknown minerals.
Lesson 2-1
Physical Properties (cont.)
•  Color alone cannot be used for mineral
identification because many different
minerals can be the same color.
•  Variations in color reflect the presence
of different types of chemical
impurities, such as iron, chromium, or
manganese.
Lesson 2-1
Physical Properties (cont.)
•  The way a mineral reflects or absorbs
light at its surface is called luster.
•  Minerals that are also
metals, such as copper,
silver, and gold, reflect
light and produce the
shiniest luster, called
metallic luster.
DEA/A.RIZZI/Getty Images
Lesson 2-1
Physical Properties (cont.)
•  Luster is directly related to the
chemical composition of minerals.
•  Streak is the color of a mineral in
powdered form.
•  Streak is only useful for identifying
minerals that are softer than porcelain.
•  Nonmetallic minerals generally
produce a white streak.
Lesson 2-1
Physical Properties (cont.)
•  Many metallic minerals produce
characteristic streak colors.
•  Hardness is the resistance of a
mineral to being scratched.
•  Friedrich Mohs developed the Mohs’
hardness scale to compare the
hardness of different minerals, with
scale ranging from 1 to 10.
Lesson 2-1
Lesson 2-1
Physical Properties (cont.)
•  Sometimes the way a mineral breaks
provides clues to its identity.
•  The arrangement of atoms or ions and
the strengths of their chemical bonds
determine how a mineral breaks.
•  Minerals break where bonds between
atoms or ions are weak.
Lesson 2-1
Physical Properties (cont.)
•  If a mineral breaks with smooth, flat
surfaces, it has cleavage.
•  If a mineral breaks and forms uneven
surfaces, it has fracture.
Lesson 2-1
Physical Properties (cont.)
•  The density of a mineral is also helpful
in identifying it. The density of an
object is equal to its mass divided by
its volume.
•  Some minerals have special
properties, such as texture, odor,
fluorescence, magnetism, or the way
they react when they come in contact
with hydrochloric acid.
Lesson 2-1
Minerals are valuable resources used to
construct many parts of a home.
Lesson 3-1
Mineral Resources
•  Rock that contains high enough
concentrations of a desired substance
that it can be mined for a profit is called
an ore.
•  Ores of the elements iron (Fe) and
aluminum (Al) are among the most
abundant of the metallic mineral
resources used every day.
Lesson 3-1
Mineral Resources (cont.)
•  Aluminum is abundant in Earth’s crust
but rarely occurs as a native element.
•  Gold occurs in a ration of 1 part gold to
4 billion parts rock in Earth’s crust, but
in large enough concentrations to be
mined for profit.
•  The technology industry is dependent
upon metallic mineral resources like
platinum.
Lesson 3-1
Mineral Resources (cont.)
Humans use
nonmetallic minerals
that are not ores,
such as the raw
materials used for
road construction,
building stone, and
fertilizers.
Construction site: Sascha/Photonica/Getty Images
Limestone block: Joel Sartore/National Geographic/Getty Images
White gravel: Mark Harwood/Getty Images
Sand: Siede Preis/Getty Images
Lesson 3-1
Mineral Resources (cont.)
•  A gemstone is a rare
and attractive mineral
that can be worn as
jewelry after it is cut
and polished.
Lesson 3-1
Mineral Resources (cont.)
•  The physical properties of gemstones
also make them useful in industry.
•  Sometimes human-made gems are
less expensive than the same natural
gems.
Lesson 3-1