Download Minerals

Rocks & Minerals
Element Quiz: Give the Symbol
1.
2.
3.
4.
5.
Oxygen
Hydrogen
Iron
Potassium
Silicon
6. Aluminum
7. Calcium
8. Sodium
9. Carbon
10. Magnesium
Answers to the Quiz
1.
2.
3.
4.
5.
O
H
Fe
K
Si
6. Al
7. Ca
8. Na
9. C
10. Mg
Minerals
What is a Mineral?
Naturally Occurring
 Inorganic
 Solid
 Definite Chemical Formula
 Definite Crystal Structure

Naturally Occurring



Formed by natural processes not in the
laboratory.
Minerals are inorganic- are not alive
Example


Salt is a mineral
Sugar is not – it was harvested from plants
Bling Bling


Diamond is a mineral
Cubic zirconia is NOT
Definite Crystal Structure

Highly ordered atomic arrangement of
atoms in regular geometric patterns
Apatite
Feldspar
Diamond
Quartz
8
Definite Chemical Formula

Minerals are expressed by a specific
chemical formula
-Gold (Au)
-Calcite (CaCO3)
-Quartz (SiO2)
-Pyrite
(FeS2)
Composition of the Earth’s Crust
 Eight Elements that make up over 98%
of Earth’s Crust
-Oxygen (O)
-Silicon (SI)
-Aluminum (Al)
-Iron (Fe)
-Calcium (Ca)
-Sodium (Na)
-Potassium (K)
-Magnesium (Mg)
Where Do Minerals Come
From?
 Precipitation
 Crystallization
of Magma
 Pressure and Temperature
 Hydrothermal Solutions
Precipitation
Earth water sources contain dissolved
substances which can react to form
minerals
Evaporation
Crystallization from Magma
As magma cools elements combine to form
minerals
Magma
Temperature and Pressure

Form when existing minerals are subject
to changes in temperature and pressure
Hydrothermal Solutions

When very hot water and substances
come in contact with one another
reactions occur and minerals can
form
How Are Minerals Identified?








Color
Luster
Hardness
Streak
Density
Crystal Shape
Cleavage and Fracture
Special Properties
Color

Usually the first and most easily observed
-Some minerals are always the same color
-Some minerals can have many colors
ROSE QUARTZ
QUARTZ
SMOKY QUARTZ
Luster

General appearance of a mineral surface in
reflected light
Glassy-Obsidian
Hardness

Resistance to scratching by different
items; “scratchability”
Mohs Hardness Scale
>2 fingernail
3 penny
~5 Steel of a pocket knife
5.5 Window Glass
6.6 Steel of a file
7 quartz crystal
Mohs Mineral Hardness Scale
1) Talc
Softest
2) Gypsum
3) Calcite
1
5
4) Flourite
5) Apatite
9
2
6) Feldspar
6
7) Quartz
8) Topaz
3
7
9) Corundum
10) Diamond
10
Hardest
4
8
Streak


The color of a finely powdered mineral
Determined by rubbing the mineral on a piece
of unglazed porcelain (streak plate)
Density

The amount of matter in a given space
(Mass/Volume)
Crystal Shape

Minerals have a characteristic crystal
shape resulting from the atomic packing of
the atoms when the mineral is forming
Cleavage and Fracture


Cleavage is the tendency of a mineral
to split or crack along parallel or flat
planes
Fracture occurs when a mineral breaks
at random lines instead of at consistent
cleavage planes.
BIOTITE
1 Direction of Cleavage
QUARTZ
No Cleavage
Obsidian
Conchoidal Fracture
Special Properties





Magnetism (Magnetite)
Glowing under ultraviolet light (Fluorite)
Salty taste (Halite)
Smell (Sulfur)
Magnetite
Reaction to HCl (Calcite)
Economic Importance of Minerals

Minerals are in many things we see and
use everyday such as; bricks, glass,
cement, plaster, iron, gold
Every American Requires 40,000
Pounds of New Minerals per Year

at this level of consumption the average newborn infant
will need a lifetime supply of:
-795 lbs of lead (car batteries, electric components)
-757 lbs of zinc (to make brass, rubber, paints)
-1500lbs of copper (electrical motors, wirings
-3593 lbs aluminum (soda cans, aircraft)
-32,700 lbs of iron (kitchen utensils, automobiles,
buildings)
-28,213 lbs of salt (cooking, detergents)
-1,238,101 lbs of stone, sand, gravel, cement (roads,
homes, etc.)
Minerals Pop Quiz
1
2
3
4
What are two characteristics of a
mineral?
Define Luster.
What is one way minerals form?
Why is color not the best way to
identify a mineral?