Minerals

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Minerals
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What is a Mineral?

• Naturally-formed solid substance with a crystal
  structure

Pyromorphite
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What do all minerals have in common?

• All
• Are formed by natural processes.
• Have a definite volume and shape (it is a SOLID)
• Are elements or compounds with a unique chemical
  makeup
• Are made up of particles that are arranged in a
  pattern that is repeated over and over (called a
  CRYSTAL)
• Are not alive and never were!

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• An element is made up of one specific type of
  atom.
• Examples
• Gold is made up of only gold atoms.
• Silver is made up of only silver atoms.

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• .What element are diamonds made from?
• . What do all crystals have in common?

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Groups of Minerals

• Minerals are grouped by the elements they are
  made of.

Beryl (Emerald)
Calcite
Amethyst
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MICA
Quartz
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Silver
Copper
Diamond
Gold
Iron
Ruby
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Calcite with Duftite inclusions
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BariteBaSo4
Barite on Calcite BaSo4 / CaCO3
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How do minerals form?

• 1) Cooling of magma (hot, liquid rock and
  minerals inside the earth (from the mantle))
• Fast Cooling No Crystals (mineraloids)
• Medium Cooling small crystals
• Slow Cooling large crystals

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How do minerals form?

• 2) Elements dissolved in liquids (usually water)

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Physical Properties of Minerals (can be used to
identify the mineral)

• Color
• Can be misleading
• Can vary with the type of impurities

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Physical Properties of Minerals (can be used to
identify the mineral)

• Luster
• Surface reflection
• metallic shiny like metal
• non-metallic dull, non-shiny surface

Pyrite has a metallic luster
Calcite has a non-metallic luster
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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

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Streakcan help identify quartz
BUT...
http//www.childrensmuseum.org/geomysteries/cube/b
3.html
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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)

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Physical Properties of Minerals (can be used to
identify the mineral)

• Cleavage Fracture
• The way the mineral breaks
• Cleavageminerals break along smooth, flat
  surfaces and every fragment has the same general
  shape
• Fractureminerals that break at random with rough
  or jagged edges

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Cleavage or Fracture?
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Physical Properties of Minerals (can be used to
identify the mineral)

• Other Properties
• Specific gravity (excellent clue to minerals
  identity)
• Attraction to magnets
• Bending of light
• Reaction with hydrochloric acid
• Smell taste

http//www.childrensmuseum.org/geomysteries/cube/b
4.html
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Watch Classifying Minerals Clip