Download minerals

DSL #27
Identify each statement as either True or
False.
1. Fossil fuels formed millions of years ago
from decayed plants and animals.
2. Most places have winds strong enough to
generate electricity.
3. All minerals are solids, but not all solids
are minerals.
4. The word crystalline means that atoms
are arranged in a repeating pattern.
What is a Mineral?

Naturally-formed solid substance with a
crystal structure
Pyromorphite
What do all minerals have in
common?

Formed by natural processes.

Are Inorganic

Have a unique chemical composition (makeup)

Have a crystalline shape- they have a definite
volume and shape
How are Minerals classified or
grouped?



90 elements occur
naturally in the Earth’s
crust.
About 98% of the
crust is made of only 8
of these elements
The most common
minerals belong to the
Silicates
Beryl
(Emerald)
Amethyst
Calcite
Mineral
Group
Characteristics
Contain
Silicates
oxygen & silicon
The most abundant
group of minerals
MICA
Examples
Quartz
Mica
Feldspar
Quartz
Mineral
Group
Characteristics
Make
up only 5% of the
Non- Earth’s crust
Silicates Include some of the
most important minerals
Silver
Examples
iron, copper,
gold, silver,
diamonds,
rubies
Diamond
Gold
Copper
Iron
Ruby
How do minerals form?
There are 2 ways that
crystals form:

The cooling of hot, liquid
rock called magma causes
compounds to combine
Rapid Cooling = Small
Crystals
 Slow Cooling = Large
crystals


The evaporation of water
that has minerals
dissolved in it
How do we identify Minerals?


We look at Physical Properties
These include:

Color/Appearance

Luster

Streak

Hardness

Cleavage/Fracture
Physical Properties of Minerals
(can be used to identify the mineral)
Color

Can be misleading

Many minerals will have
a similar appearance,
but will have different
impurities
Physical Properties of Minerals
(can be used to identify the mineral)
Luster
 Luster refers to the way a mineral
reflects light
 Metallic = shiny like metal
 Non-metallic = dull, non-shiny surface
Pyrite has a
metallic luster
Calcite has a nonmetallic luster
Physical Properties of Minerals
(can be used to identify the mineral)
Streak
 The color of the
powdered form of the
mineral
 The color of the streak
can be different than the
mineral
 Minerals must be softer
than the streak plate
Streak…can help identify quartz
http://www.childrensmuseum.org/geomysteries/cube/b3.html
Physical Properties of Minerals
(can be used to identify the mineral)
Hardness
 How easily a mineral scratches materials
 Mohs Hardness Scale
Scale from 1 (softest) to 10 (hardest)
 Test by seeing if the mineral can scratch different
objects (like human fingernail, copper, penny, glass,
steel file)

Physical Properties of Minerals
(can be used to identify the mineral)
Cleavage & Fracture



The way the mineral
breaks
Cleavage—minerals
break along smooth, flat
surfaces and every
fragment has the same
general shape
Fracture—minerals that
break at random with
rough or jagged edges
Cleavage or Fracture?
1.
3.
2.
4.
Physical Properties of Minerals
(can be used to identify the mineral)
Review
1.
What is a Mineral?
2.
Name 2 things that all minerals have in
common?
3.
A naturally occurring solid with a
crystal structure
Inorganic, Crystalline Structure, Formed Naturally,
Unique Chemical Composition
The mineral group, Silicates, is made up of
what two elements?
4.
Oxygen and Silicon
How are minerals identified?
Color, Luster, Streak, Hardness, Cleavage, Fracture