Properties of Minerals

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Properties of Minerals
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Hardness - resistance to being scratched

• Mohs Hardness Scale
• ranges from 1(talc) to 10 (diamond)
• a mineral will only scratch those softer than
  it
• Field scale
• common test using fingernail (1), penny (3),
  glass (6)

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Color- not a reliable indicator of identity due
to weathering and impurities
Look at the 2 fluorite samples.
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Streak the colored powder left when rubbed
against a hard surface (more reliable than color
because streak is not affected by weathering)
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Luster ability to reflect light on its
surface glassy metallic submetallic nonmetall
ic
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Cleavage Fracture the way a mineral breaks
when stressed Cleavage the tendency to break
along flat surfaces and smooth lines (along weak
bonds) Fracture the quality of the break
typically uneven along curved or irregular
surfaces if minerals atomic bonds are strong
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Crystal Shape the natural growth of a mineral
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Taste certain minerals like halite (salt) and
sulfur have characteristic flavors (only water
soluble minerals do)
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Specific gravity the ratio of an objects
density to the density of waterMagnetism
Magnetite has magnetic properties
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Reaction to Acid an acid, such as hydrochloric
acid (HCl), can cause a mineral to fizz
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Fluorescence Calcite and fluorite can glow under
UV light.
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Optical properties Calcite can create a double
image
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Idioms to Ponder

• Back to the salt mines
• Sitting on a gold mine

the need to return to work or some activity that
is not fun in control of something valuable