Unit 9
Rocks and Minerals
Topic: Minerals
 Key terms:




Matter
Elements
Atoms
Mineral
Mineral Uses
Quartz
Graphite
Halite
Talc
Gypsum
How many different
minerals are there?
 4,000 known minerals, according to the
International Mineralogical Association
Elements
-
Matter
-
Atoms




made of three particles
Protons
=
Positive
Neutrons =
Neutral
Electrons =
Negative
(+)
(0)
(-)
Take out ESRT pg 1
Atoms make up
Elements…
Elements make up
MINERALS!!!
What is a mineral?
1) Solid
2) Inorganic: not, or never was,
living
3) Definite chemical composition
 Elements that make up the mineral
 Example:
Mineral Halite (aka Salt)
Composition: Sodium (Na) & Chlorine (Cl)
Chemical Formula: NaCl
4) Crystalline structure
The pattern of molecules repeated
throughout the mineral –
gives a mineral it’s properties!
5) Naturally Occurring
Silicon Tetrahedron
-
Review: What is a mineral?





-
Final Question:
 Can water, H2O, ever be considered a
mineral? If so, how?
Topic: Identifying Minerals
 Key Term:






Color
Streak
Hardness
Luster
Cleavage
Fracture
*-
Look at the last
page of ESRT
to find the
minerals you
need to know.
On the
mineral
chart
Elements that
make up the
minerals
Tests for Identifying Minerals
Test 1: Color Test
Test 1: Color Test
*Color is not the best property to use when
identifying a mineral. Why?
1) 2) -
Test 2: Luster
 Luster -
Metallic -
Non-metallic -
Luster
All minerals
Metallic
Non-Metallic
dull
glassy
pearly
Luster
Examples of
Metallic Luster
Pyrite, Galena
Luster
Examples of NonMetallic Luster
(Dull) Earthy Corundum
Glassy Quartz
Pearly Opal
Find Hematite on mineral chart
 What is unique about hematite’s luster?
Either
Test 3: Streak Test
 The streak -
We use a streak plate
Where is streak on the chart?
Look under
Distinguishing
characteristics
to find streak
Pyrite is a
brassy
yellow, but in
a powder is
green-black
What is the color of hematite's streak?
Test 4: Hardness Test
 A mineral’s hardness is -
Hardness Test
 Mohs Scale of Hardness (1-10)
1.
2.
3.
4.
5.
Talc
Gypsum
Calcite
Fluorite
Apatite
6.
7.
Feldspar
Quartz
8. Topaz
9. Corundum
10. Diamond
Hardness Tools






Fingernail
Penny
Iron Nail
Glass Plate
Steel File
Streak Plate
2.5
3.5
4.5
5.5
6.5
7
Hardness Test
Talc = hardness of 1
Diamond =
hardness
of 10
Test 5: The way a mineral
breaks
1) Cleavage -
 Basal Cleavage: Mica
 Cubic Cleavage: Halite
 Rhombohedral Cleavage: Calcite
2) Fracture- -
Rose Quartz
 Splintery Fracture: Hornblende
 Conchoidal Fracture: Obsidian
The check
indicates if a
mineral has
fracture or
cleavage
Watch out for Crystals
Pyrite – looks like
flat surfaces,
however these
crystals did not
break, they grew
into this shape.
Other identification tests
HCl
Acid
 Acid Test
for Calcite
and Dolomite
 HCl—
bubbles or
fizzes
Calcite
 Smell Test for Sulfur
 Smells like rotten eggs
 Magnetism for Magnetite
 Taste Test for Halite
Optical Properties – Double refraction
Mineral – Iceland Spar Calcite
Fluorescence: some minerals glow
under ultraviolet light
Franklinite
from
Franklin,
New
Jersey
Compare Diamond and
Graphite
Graphite
Chemical Composition
is Carbon (C)
Diamond
Chemical Composition
is Carbon (C)
Can we use a diamond like we use graphite?
Arrangement of atoms