MINERALS CH5

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MINERALS CH5

• Mineral a solid naturally formed inorganic
  substance that always has the same composition
  and the same properties.
• Rock a naturally formed combination of minerals.

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MINERALS

• GEM mostly minerals with exceptional brilliance
  color durability and rarity- There are over 3300
  different minerals.

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MINERAL CHARACTERISTICS

• Inorganic like Fluorite CaF2, not coal
• Occur naturally like Halite NaCl but not steel
  (an alloy of Iron and Carbon)
• Crystalline solid has to be repeating crystals
  like Quartz SiO2 not Obsidian

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MINERAL CHARACTERISTICS

• Consistent Chemical Composition Like Hornblende
  Ca2(Mg,Fe)4Al(Si7Al)O22(OH,F)2 and not Basalt
  which can have a variety of minerals

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MINERALS

• Strategic metals and minerals Those minerals and
  metals that are critical to the national
  interests.

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KINDS OF MINERALS

• Silicate Minerals have Silicon in their
  composition evidenced by the crystalline
  Silicon-Oxygen tetrahedral crystal

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KINDS OF MINERALS

• Nonsilicate minerals form a myriad of shapes
  including tetrahedrons that do not have silicon
  in the middle, shapes are cubes, rhomboids,
  hexagonal prisms and irregular masses. High
  density is a key to these

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MINERAL PROPERTIES

• Color Probably the most obvious but the least
  reliable.
• Streak The color of the powder left when it is
  rubbed on a rough surface. Better than color for
  ID.
• Luster the appearance of the mineral surface in
  light

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MINERAL PROPERTIES

• Density Mass divided by volume. A good indicator
  as it does not change with the size of the
  sample.
• Specific Gravity a comparison of the weight of a
  specific volume of the mineral to that of water

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MOHs Hardness Scale

• Hardness Mohs scale of mineral hardness page 111
  properties for ID

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Mohs Hardness Scale

• Talc rub your thumb
• Gypsum scratch with a fingernail
• Calcite scratch with a penny
• Fluorite scratch with a nail
• Apatite scratch with a nail
• Orthoclase will not scratch glass nail will not
  scratch
• Quartz scratches glass
• Topaz scratches glass
• Corundum (ruby and sapphire) scratches glass
• Diamond scratches everything

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MINERAL PROPERTIES

• Cleavage Minerals that break along flat planes.
  Minerals may cleave in one two or three
  directions.
• Fractures minerals that break along uneven
  edges.
• Crystals page 112 the shape that a mineral grows
  in.

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Unique Properties of MINERALS

• Magnetism magnetite and hornblende
• Taste Halite (salt)
• Smell Sulfur
• Chemical reaction Calcite will fizz when exposed
  to weak HCL.
• Some materials give off light when exposed to
  ultra violet radiation.