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Section-2 Mineral Identification pg.68 - Marysville Schools

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Section-2 Mineral Identification pg.68 - Marysville Schools Powered By Docstoc
					 Describe physical properties used to
  identify minerals.

 Identify minerals using physical properties
  such as hardness and streak.
   Mineral appearance
   Hardness
   Luster
   Specific gravity
   Streak
   Cleavage and fracture
   What it looks like
   What color is it?
   Which one of the following is gold? Identify by
    appearance.
   A measure of how easily a mineral can be
    scratched
                  Mohs Hardness Scale
Mineral    Rating      Testing Method
Talc         1         Softest known mineral. It flakes easily when
                       scratched by a fingernail.
Gypsum       2         A fingernail can easily scratch it.
Calcite      3         A fingernail cannot scratch it, but a copper
                       penny can.
Fluorite     4         A steel knife can easily scratch it.
Apatite      5         A steel knife can scratch it.
Feldspar     6         Cannot be scratched by a steel knife, but it
                       can scratch window glass.
Quartz       7         Can scratch steel and hard glass easily.
Topaz        8         Can scratch quartz.
Corundum     9         Can scratch topaz.
Diamond      10        Hardest known mineral. Diamond can
                       scratch all other substances.
   The way a mineral reflects light is luster.
   Luster is either metallic or nonmetallic.
   Specific gravity can be compared to density.
   The specific gravity of a mineral is the ratio of
    its mass compared with the mass of an equal
    volume of water.
   Gold has specific gravity of 19.
   It means gold is 19 times more dense
    than water.
                 Gold is
                 19 times heavier,
                 19 times more dense
                 than water.
   When a mineral is rubbed across a piece of
    porcelain tile a streak of powdered mineral is
    left behind.
•   Cleavage is the way a mineral breaks along
    smooth, flat surfaces.
•   Mica and calcite have cleavage.
   Minerals that break unevenly with rough or
    jagged surfaces have fracture.
   Quartz has fracture.




                               quartz
CLEAVAGE   FRACTURE
http://www.youtube.com/watch?v=VnM8ebB06MU
   Gems (or gemstones) are highly prized
    minerals because they are rare and beautiful.
       They are cut to sparkle.
       Amethyst gets its purple color from a bit of iron.
   Cullinan diamond
       Found in S. Africa in 1905
       Largest uncut diamond ever found
       Cut into 9 main stones and 96 smaller ones
       Largest is called “Great Star of Africa.”
       Belongs to the British monarchy.
   Hope diamond
       Most famous gem
       Blue in color
       Thought to be cursed
       In the Smithsonian in Washington, DC
   Waste diamonds are used in industry as
    abrasives and embedded on cutting tools, such
    as saw blades and drill bits.
   Quartz crystals are used in electronics and in
    timepieces. They vibrate and can control
    frequencies.
   Rubies and emeralds are used in lasers.
   Most industrial gems are synthetic, meaning
    manmade.
   Minerals are often found in ores.
   Ores are minerals or rock that contains a useful
    substance AND can be mined at a profit.
   Bauxite
       Yields aluminum through smelting.
       Smelting is a process where a rock is crushed and the
        metals are melted out of the rock.
   Hematite and magnetite
       Yield iron used in construction, cars, and many other
        applications where steel is needed.
   Ilmenite and rutile
       Yield titanium
   Some metallic elements can dissolve in fluids.
   These fluids travel through cracks in rocks and
    form mineral deposits
   These are called vein minerals.
   Includes:
       gold
       silver
       copper
       zinc
   Titanium is used in
     Auto body parts
     Tennis rackets
     Bicycles
     Wheelchairs
     Glasses frames
     Replacement joints

				
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