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• Physical properties of minerals

  • Luster
  • Hardness
  • Color and streak
  • Crystal form and habit
  • Cleavage and fracture
  • Specific gravity
• Luster


  The way surface reflects light, "looks shiny"
• Luster classifications

  • Nonmetallic
  • Metallic
  • Submetallic
• Hardness

  Resistance to being scratched, Moh's hardness scale used by scientists to describe the hardness of materials, Harder to scratch = higher rating, Least hard: Talc - 1, Most hard: Diamond - 10
• Color


  A mineral's color can change due to different chemical reactions, One type of mineral can have different colors
• Pyrite "fool's gold"


  • Gold color
• Streak

  Color of mineral in powdered form, can be found by rubbing mineral against unglazed porcelain (streak plate), mark left on streak plate is the streak, more useful in identifying minerals than color, because color can change due to chemical reactions and one type of mineral can have multiple colors, the streak of a mineral is always the same, streak is more reliable in identifying a mineral because the streak is the true color
• Hematite


  • Red-brown streak
• Cleavage and fracture


  Different materials break in different ways, the way a mineral breaks depends on how its atom arrangement, surfaces that form are smooth and flat (cleavage), break unevenly along curved or rough surfaces (fracture)
• Density

  Measure of how much matter is in a given amount of space, measured in grams per cubic centimeter (g/cm3), Geologists use a specific gravity to describe the density of the mineral, Specific gravity: density of the mineral divided by the density of water (1 g/cm3)
• Gold

  • Density of 19 g/cm3, specific gravity of 19
• Fluorescence

  Glow under UV light, calcite and fluorite
• Chemical reactions

  Calcite produces gas bubbles and fizzes when a drop of weak acid is poured
• Optical properties

  Images look doubled when viewed through certain minerals
• Magnetism

  Natural magnet, attracts metallic objects, magnetite
• Taste

  Halite has a salty taste, taste can be influenced by the chemical composition
• Radioactivity

  Radioactive elements, radiation can be detected by Geiger counter
• Fluorescence


  • Glow under UV light
  • Calcite and fluorite exhibit this property
• Chemical Reactions

  Calcite produces gas bubbles and fizzes when a drop of weak acid is poured
• Optical Properties

  • Images look doubled when viewed through certain minerals
• Magnetism

  • Natural magnet
  • Attracts metallic objects
  • Magnetite exhibits this property
• Taste

  - Halite has a salty taste

  - Taste can be influenced by the chemical composition
• Radioactivity

  • Radioactive elements
  • Radiation can be detected by Geiger counter
• Classification of Minerals

  • Silicates
  • Oxides
  • Sulfates
  • Sulfides
• Silicates

  Composed of silicon-oxygen tetrahedrons (SiO4)

  - the fundamental building block of silicate minerals

  - 90% of rock-forming minerals belong here

  - Examples: feldspar, mica, quartz, pyroxene, olivine
• Oxides


  Minerals containing Oxygen anion (O2-) combined with one or more metal ions

  - Common oxide minerals are magnetite (Fe3O4) and Hematite (Fe2O3)
• Sulfates

  Contain Sulfur and Oxygen anion (SO4) combined with other ions (metal cation)

  - Usually precipitate out of water near Earth's surface

  - Example: Gypsum
• Sulfides

  Contain sulfur anion (S2-) combined with one or more ions

  - Economically important metals