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Mineral IdentificationMineral Identification
What you’ll learn
•Describe physical properties used to identify minerals.
Common uses of Rocks and Minerals
• Have you ever used a Mineral?
• YES!!!!!!!
• Minerals are all around us.
Introduction
• Many of the items used in our homes and in industry are made of materials that were mined from the ground.
• There are thousand of known minerals .
• It is estimated that every person in the USA will use more than a million pounds of rocks, minerals and metals during their lifetime.
Important Physical Properties Important Physical Properties used in the identification of used in the identification of
minerals minerals • Color
• Hardness
• Luster
• Specific gravity
• Streak
• Cleavage and fracture
• Interaction with light
• Reaction with Acid and Water
Color • The color of the mineral helps you with
identification, but sometimes, the same mineral have different colors
LusterLuster • It is the way a mineral reflects light.
• Either metallicmetallic or nonmetallicnonmetallic
Light Interaction - Put the Light Interaction - Put the mineral on top of your book. If it mineral on top of your book. If it
is:is:
• Opaque – no light pass through the mineral. You can’t see through
• Translucent – some light can pass through, but you can’t see through the mineral
• Transparent – light rays can pass through the mineral and you can see letters from the book right through it.
StreakStreak
• Rub a mineral across a piece of porcelain tile.
• a streak of powdered mineral is left behind.
• The color of the streak will help you identify the mineral, because sometimes is different than the color of the mineral.
HardnessHardness
• A measure of how easily a mineral can be scratched by another mineral or other materilas
• For this test you use the Mohr’s Scale in the back of your handout
Ex of a Mohs ScaleMohs Hardness Scale
MineralTalc
Gypsum
Calcite
Fluorite
Apatite
Feldspar
Quartz
Topaz
Corundum
Diamond
Rating
1 Softest known mineral. It flakes easily when scratched by a fingernail.
2 A fingernail can easily scratch it.
3 A fingernail cannot scratch it, but a copper penny can.
4 A steel knife can easily scratch it.
5 A steel knife can scratch it.
6 Cannot be scratched by a steel knife, but it can scratch window glass.
7 Can scratch steel and hard glass easily.
8 Can scratch quartz.
9 Can scratch topaz.
10 Hardest known mineral. Diamond can cut or scratch all other substances.
Testing Method
Cleavage/ Fracture - the way a Cleavage/ Fracture - the way a mineral breaksmineral breaks
• Minerals that break along smooth, flat surfaces have cleavage.
• Minerals that breaks uneven, rough, or jagged surfaces have fracture.
Reaction with Acid
• Some minerals will fizz in contact with acids
• Others can dissolve in contact with water
• Also these properties will help identify a mineral