Download Minerals - McEachern High School

Chapter 4: Section1
What Are Minerals?
Minerals
–a
naturally occurring,
inorganic solid that
has a crystal
structure and a
definite chemical
composition
What 5 Characteristics Does
a Mineral Have to Have?
A mineral must be:
 Naturally
 Inorganic
 Solid
 Crystal
Occurring
Structure
 Definite Chemical
Composition
What Does It Mean to Be
Naturally Occurring?
A mineral must occur
naturally
Cement,
brick, steel, and
glass all come from
substances found in
Earth’s crust but they
are manufactured by
people
How Can Something Be Inorganic?
Inorganic
– the mineral
cannot arise from
materials that were once
part of a living thing
Ex. Coal is NOT a mineral
because it is made up the
remains of plants and
animals
What kind of pattern must a
mineral have?
A
mineral must have a
crystal structure – a
repeating pattern of a
mineral’s particles that
forms a solid.
Faces – a crystal’s flat
side that meets at
sharp edges and corners
What kind of composition must
a mineral have?
A mineral must have
a definite chemical
composition – it
always contains
certain elements in
definite proportions;
most minerals are
compounds
Cinnabar –
composed of the
elements Mercury
and Sulfur
What Is the Difference Between an
Element and a Compound?
Element
– a substance composed of
a single kind of atom. Ex.
Hydrogen
Two or more
elements combined so that the
Compound
–
elements no longer have distinct
properties Ex. Water H20
How Do You Identify Minerals?
Properties:
Density
Crystal
Shape
Cleavage and
Fracture
Special
Properties
Hardness
Color
(this
can vary)
Streak
Luster
How Do You Determine a
Mineral’s Hardness?
Friedrich
Mohs invented a
test to describe and
compare the hardness of
minerals
Mohs Hardness Scale
Ranks ten minerals from
softest to hardest
How Does the Mohs Scale Work?
Gypsum
(2) will
scratch talc (1),
calcite (3) will
scratch gypsum
(2), fluorite (4)
will scratch
calcite (3), etc.
What Is a Streak Test?
The
streak of a
mineral is the color of
its powder
The streak color and
the mineral color are
often different
To test: rub a mineral
against an unglazed
tile (streak plate)
What is the Luster of a
mineral?
Luster
– used to describe
how a mineral reflects
light from its surface
Minerals containing
metals are often shiny
Earthy, waxy, and pearly
What does Density have to do
with Minerals?
Each
mineral has a characteristic
Density
Density – or mass per unit volume;
Density = mass/volume
Displacement – the volume of the
displaced water equals the volume
of the the sample
What Kind of Shape does a
Mineral have?
Minerals
Cubic
have a crystal structure
Hexagonal
Tetragonal
Orthorhombic
Monoclinic
Triclinic
What is Mineral Cleavage?
Cleavage
–A
mineral’s ability to
split easily along a
flat surface
The
ability to
break apart
depends on the
arrangement of
the atoms in the
mineral
Cubic
Cleavage
Basal Cleavage
What is Mineral Fracture?
Fracture
– How a mineral
looks when it breaks apart in
an irregular way
What Special Properties does a
Mineral have?
 Fluorescence
–minerals that glow under
ultraviolet light
 Magnetism
- ex. Loadstone
 Chemical
Reactivity- ex. Calcite gives off
carbon dioxide
 Electrical
Properties – ex. quartz
Section2:
How are Minerals Formed?
 Two
General Ways:
Crystallization of melted materials
Minerals
from Magma
Crystallization
of materials dissolved in
water
Minerals from Hot water
solutions
Minerals
formed by evaporation
What is Crystallization?
Crystallization
the process by which atoms
are arranged to form a
material with a crystal
structure

How do Minerals form from
Magma?
Minerals
form as magma
cools inside the crust, or as
lava hardens on the surface
What Effects Crystal Size?
Rate
at which magma cools
Slower cooling forms
larger crystals
The amount of gas the
magma contains
The chemical composition of
the magma
How do Minerals Form from Hot
Water Solutions?
Magma beneath Earth’s surface
has heated the water to a high
temperature beneath Earth’s
surface causing minerals to
dissolve
When
this solution cools the
elements and compounds leave
the solution and crystallize as
minerals
What is a Solution?
Solution
– A mixture in
which one substance
dissolves in another
What do Pure Metals often
form from Hot Water
Solutions?
 Veins
– A narrow channel or
slab of a
mineral that is much different from
the surrounding rock
How are Minerals Formed
by Evaporation?
As
water turns to vapor it
leaves behind the mineral
Example: A salt water
solution leaves behind large
crystals of salt
Where are Minerals Found?
Earth’s
crust is made up of a
variety of minerals however;
rare and less common minerals
are usually located near plate
boundaries because of volcanic
activity and mountain building
Section 3: How are Minerals
Used?
Minerals are the source of
Metals ex. Aluminum, Iron
Gemstones ex. Rubies and
Sapphires
Other Useful materials ex. Talc
(talcum powder)
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