Mineral Identification

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Mineral Identification
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• 7 properties used to identify minerals
• Color
• Luster
• Streak
• Cleavage/Fracture
• Hardness
• Density
• Special Properties

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• Color
• Not a good way to identify minerals
• The same mineral can come in a variety of colors
  ex Quartz (pink, grey, purple)
• Impurities can cause the colors to change

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• Luster
• The way the minerals surface reflects light
• Shiny
• Metallic luster
• Dull
• Submetallic, nonmetallic luster

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• Streak
• The color of a mineral in powder form
• Can be found by rubbing the mineral against a
  streak plate
• The color of a streak is not always the same as
  the mineral
• Streak is more reliable than color

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• Cleavage/Fracture
• Minerals break in different ways depending on
  atom arrangement
• Cleavage
• The tendency of some minerals to break along
  smooth surfaces
• Fracture
• The tendency of some minerals to break unevenly
  along curved or irregular surfaces

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• Hardness
• A minerals resistance to being scratched
• Mohs Hardness Scale
• 1. Talc 6. Orthoclase
• 2. Gypsum 7. Quartz
• 3. Calcite 8. Topaz
• 4. Fluorite 9. Corundum
• 5. Apatite 10. Diamond
• The higher the number the harder the mineral

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• Density
• Measure of how much matter is in a given amount
  of space
• Water is used as a reference because it has a
  density of 1 g/cm³

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• Special Properties
• Fluorescence (Calcite/Fluorite)
• Chemical Reactions (Calcite)
• Magnetism (Magnetite)
• Taste (Halite)

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Question 1

• What are the seven properties used to identify
  minerals?

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Answer

• Color, Luster, Streak, Cleavage/Fracture,
  Hardness, Density, Special Properties

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Question 2

• Why is mineral color not a good way to identify
  different minerals?

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Answer

• The same minerals can have multiple colors which
  makes it a poor property when used in
  identification.

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Question 3

• How do you determine a minerals streak?

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Answer

• The streak is determined by rubbing the mineral
  against a streak plate until there is a thin
  layer of powder