Chapter 3- Minerals
Section 1- Properties of Minerals
What is a Mineral?
• Mineral= a naturally occurring, inorganic solid
that has a crystal structure and a definite
chemical composition
5 Characteristics of Mineral
1. Naturally occurring- found in the natural world
- Not natural (plastic, steel, brick, concrete)
2. Inorganic= not formed from a living thing or
once living thing
What is a Mineral?
5 Characteristics cont…
3. Solid
4. Crystal Structure
- Crystal= the repeating
pattern of a mineral’s
particles
5. Definite chemical
composition (make-up)=
contain certain elements in a
definite proportions
Identifying Minerals?
5 Tests for Identifying Minerals
1. Color
2. Streak color
- Streak= the color of a
mineral’s powder
* Done by rubbing the
mineral across a tile
Identifying Minerals?
5 Tests for Identifying Minerals cont.
3. Luster= measure of light reflected from a
mineral’s surface
- (Can be described as glassy, pearly, waxy,
silky, metallic)
4. Density= mass (weight) of an object in a given
space
Density =
Identifying Minerals?
5. Hardness
- Mohs hardness scale= a scale which ranks 10
minerals from softest to hardest
* Done by scratching the mineral with objects
of varying hardness (Example: fingernail=2)
Identifying Minerals?
• Minerals can also be identified by how they break
apart.
Cleavage
2 Ways Minerals Break
1. Cleavage= when a mineral
splits along a flat surface
2. Fracture= when a mineral
breaks apart in an irregular
way
Fracture
Section 2- How Minerals Form
How Minerals Form?
• Crystals form by crystallization= a process by
which atoms are arranged to form a crystal structure
2 Methods of crystallization
1. Molten material
2. Materials dissolved in
water
Cave of Crystals in Mexico
Minerals from Magma and Lava
• Magma= molten material from inside the earth that
hardens to form a rock
• Lava= magma that reaches the surface
* When magma and lava cool
they form crystals
• Rate of cooling determines
crystal size
- Slow cooling large crystals (magma)
- Quick cooling small crystals (lava)
Minerals from Solutions
• Solution= mixture in which one substance is
dissolved in another
- For example: Kool-aid in water
• Geode= a rounded hollowed out
rock lined with mineral crystals
- Formed when water enters rock
through a crack and elements
begin to crystallize on rock walls
Geode
Minerals from Solutions
• Minerals can also be formed from…
- Evaporation of a solution
leaving behind the minerals
- Hot water solutions
As hot water heated by magma
begins to cool the elements
in the water can escape and
crystallize in veins= a narrow
channel of mineral that is
different from the surrounding
rock
Gypsum Rose
Gold Vein
Section 3- Using Mineral Resources
The Uses of Minerals
• Gemstone= a hard, colorful mineral that
has a brilliant or glassy luster (Ruby,
Opal, Sapphire, diamond…)
- Jewelry, decoration, mechanical
parts for grinding and polishing
• Metals (Aluminum, iron, copper, silver)
- Very ductile and malleable
- Building frames, cars, money, jewelry
The Uses of Minerals
• Other Uses (In foods, medicines,
fertilizers and building materials)
- Talc  talcum powder
- Quartz glass, electronic parts,
and watches
- Gypsum  wallboard, cement,
and stucco
Rough Beginnings
• Minerals are obtained in
the form of an ore= a
rock that contains a metal
or other useful mineral
that can be mined and
sold as a profit
Making Metals from Minerals
First they must be
undergo…
- Prospecting- find the
mineral
- Mining- dig up the mineral
- Smelting- melting down
and removal of unwanted
material from the wanted
mineral
Making Metals from Minerals
• Further Processing
- Alloy= a solid mixture
of a metal and one or
more elements
Ex: iron + carbon= steel
*Why an alloy?
- Can give the metal better qualities (stronger,
rust resistant, shinier)
Ex: Steel + manganese makes stronger steel