Minerals
Minerals Overview
atoms
 minerals

rocks

History of the Earth
Mineral Safety Rules
Hand-to-Mouth Contact = use disposable gloves when handling minerals
and keep from touching your mouth and your eyes.
Wash Hands = after working with minerals wash your hands with soap
and water.
Samples = must remain in the classroom at all times and returned to the
kit when not in use.
Poison = most minerals are poisonous, but there is not a large enough
sample to cause major harm. DO NOT put the minerals in your mouth!
What is a Mineral?
Minerals are free uncombined elements or compounds. Their
compositions are given as chemical formulas. The formula for fluorite
is CaF2. This indicates that the calcium (Ca) atoms have combined with
fluorine (F) atoms. The subscripted number (2) shows that there are
twice as many fluorine atoms as there are calcium. Minerals are
arranged into groups according to the chemical compositions and the
crystal structure.
Minerals
There are four things that distinguish minerals.
Naturally occurring
Generally inorganic
“Constant” chemical composition
Crystalline Structure
Found in Nature
Solid substances found naturally in the Earth. Scientist have learned
to make some.
Inorganic (usually)
Not alive or produced by living process
Exceptions
graphite (pencil lead)
calcite (limestone/marble)
aragonite (pearls)
“Constant” Chemical Composition
Calcite = calcium + carbon + oxygen (CaCO3)
Calcite in its purest form is clear,
however, the impurities formed by elements change its color –
pink, green, gray, etc.
Quartz = silicon + oxygen (S1O2)
Quartz comes in a variety of colors.
Diamonds = carbon (C)
Analyzed for color, cut, clarity, and carat.
Fancy diamonds such as red, pink, purple, and blue are so rare they
are not found on a gemologists color scale.
Crystalline Structure
The pattern that the atoms arrange in to create an element is the crystalline
structure.
Halite = sodium + chlorine (NaCl)
Halite is regular table salt and has a cube-like structure.
Diamond vs. Graphite (C)
These two minerals are made of
the exact same atoms, but are
different because of their
crystalline structure.
Diamonds vs. Graphite
Diamond atoms are strong and close together.
Graphite are only strong in one direction and this makes them weak, soft,
and flexible.
Diamonds can form only at a depth of 120 km or greater within the layers
of the earth.
Scientists believe that the diamonds have been
brought up through kimberlite pipes through
some type of explosion and the surface has
eroded over millions of years to expose them.
Graphite vs. Diamond
The Structure of the elements that make up these minerals.
Mineral Properties
Luster = shiny or dull
How well does it reflect light?
Light = opaque, translucent, transparent
Will the light shine through the mineral?
Streak = color of the powdered mineral
What is the color of the mineral when powdered?
Hardness = soft or hard (MOHS Scale of Harness)
How difficult is it to scratch the mineral?
Magnetism = magnetic or not
Will iron cling to this mineral?
Texture = rough or smooth
Does it smell like something familiar?
Mineral Observations
Step-by-Step Procedures
 Step 1 - Gather materials: hand lens and minerals.
 Step 2 – Observe the minerals using hand lens and use your senses of touch, smell,
and sight.
 Step 3 – Illustrate the mineral using colored pencils.
 Step 4 – Using a dropper place a drop of water on the mineral to make it easier to
detect smell and to observe the color.
 Step 5 – Write a sentence describing the texture and smell of the mineral.
Mineral Testing
Mineral A (illustration)
Luster
Hardness
Light
Streak
Mineral Testing
Mineral A (illustration)
Luster
Dull
Hardness (Mohs Scale)
Soft (6.0 )
Light
opaque
Streak
white
Streak Color
Streak Color
Test
Light
Light
Test
Luster
Luster Test
Mohs Scale of Hardness
Way back in 1822, the German mineralogist, Friedrich Mohs
developed the 10 point hardness scale that is still used today.
Hardness
Mohs Scale of Hardness
Fredrick Mohs developed this scale to categorize minerals. Any mineral with a higher number will scratch a
mineral of a lower number.
1
Talc
Talcum powder.
2
Gypsum
Drywall and Plaster of Paris. Fingernail (2.5)
3
Calcite
Copper Penny.
4
Fluorite
Used to lower the melting temperature of iron.
5
Apatite
Window Glass, is found in teeth and bones (5.5)
6
Orthoclase
Steel File also used in ceramics (6.5),
7
Quartz
Used in electronics and glass
8
Topaz
Sandpaper, emeralds and aquamarines
are varieties of beryl with a hardness of 8.
9
Corundum
Sapphire and Ruby are types of corundum. They are
two to five times as hard as topaz. Used to grind things down.
10
Diamond
Four times as hard as corundum.
Hardness Test
Power Conclusion
1. Refers back to the prediction.
I thought that . . .
2. Answers the question.
I found out . . .
3. Future Research.
In the future I would like to . . .
Glossary
Color Streak: the color that a mineral leaves behind when
you rub it on a black or white tile.
Light: A mineral’s light transmissivity can be described as
opaque, transparent, or translucent.
Luster: describes the way the surface of the mineral
reflects light.
Mineral: a solid material with atoms arranged in a
repeating pattern.
Mohs Scale of Hardness: A scale of 10 minerals used to
compare all minerals from softest to hardest.
Glossary
Opaque: When light is not able to travel through a solid
surface .
Rock: Material made up of one or more minerals.
translucent: When some light can travel through a solid
object.
transmissivity: The ability for light to travel through a
solid object.
transparent: When all the light can travel through a
solid object. (clear)