Properties of Minerals

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Properties of Minerals
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1. Hardness - resistance to being scratched

• Mohs Hardness Scale- In 1812, the Austrian
  mineralogist Friedrich Mohs set a scale of
  mineral hardness from talc (1) to diamond (10).
  Any mineral on the scale will only scratch those
  minerals below it.
• Field scale- common test using fingernail (1),
  penny (3), glass (6)

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2. Color- not a reliable indicator of identity
due to weathering and impurities
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3. Streak leaves a colored powder when rubbed
against a hard surface. Its more reliable than
color because streak is not affected by
weathering.
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4. Density the amount of matter in a given
space, measured in grams/cm3. The ratio of an
objects density to the density of water is
called the objects specific gravity.
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5. Luster how a mineral reflects light on its
surface. Minerals can be glassy, metallic,
submetallic, or nonmetallic
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6. Fracture Cleavage different minerals have
characteristic ways of breaking. Cleavage is the
tendency to break along flat surfaces. Ex. Galena
and pyrite will always break into a
cube.Fracture is the tendency to break unevenly
along curved or irregular surfaces.
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7. Crystal Shape the natural growth of a mineral
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8. Taste certain minerals like halite (salt)
and sulfur have characteristic flavors
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9. Magnetism Ex. Magnetite has magnetic
properties.
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10. Reaction to Acid an acid, such as
hydrochloric acid (HCl), can cause a mineral to
fizz.
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11. Fluorescence Ex. Calcite and fluorite can
glow under UV light.
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12. Optical properties Ex. Calcite can create a
double image.