MINERALS

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MINERALS
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Chemical composition of the Crust

• Oxygen most abundant- 46.6
• Followed by silicon and aluminum
• Iron, Calcium, Sodium, Potassium, Magnesium
• The most common minerals will be composed mostly
  of these elements
• Silica silicates

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MINERAL vs. ROCK

• ROCK
• An aggregate of one or more MINERALS (usually-
  coal, organic)
• MINERAL
• Solid
• Crystalline- orderly arrangement of atoms
• Naturally occurring
• Inorganic
• Definite chemical composition
• e.g. SiO2 for quartz KAlSi3O8 for feldspar

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Atom Elements

• Atoms
• Neutral
• Nucleus
• Proton, neutron
• Electron
• Ions
• Electrical Charge
• Molecule- e.g. water molecule

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Chemical activity

• Stable atoms want
• positive negative charges balanced
• electron shells full
• Ions- positive (Cations) and negative (Anions)
• Bonding
• Ionic
• Covalent
• Metallic
• Van der Waals

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Element

• Atomic number
• Number of PROTONS
• Isotope
• Differing number of NEUTRONS
• Atomic weight
• Mass of PROTONS and NEUTRONS

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Crystallinity

• 3 dimensional orderliness of atoms
• Silicon-oxygen tetrahedron
• Silicate structures
• Single- e.g. olivine
• Chain
• Single chain- pyroxene
• Double chain- amphibole
• Sheet- e.g. mica, clay
• Framework- e.g. quartz, feldspar

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MINERALS

• Crystalline solids
• Natural and Inorganic Substances
• Definite chemical composition
• Can be written as a chemical formula
• Solid solution (within a range)

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Important Minerals

• Quartz (most abundant)
• FELDSPAR Group
• Potassium Feldspar - Orthoclase
• Plagioclase Feldspar
• Sodium (Na) Albite
• Calcium (Ca) Anorthosite

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Important Minerals

• PYROXENE Group- Augite most common
• AMPHIBOLE Group- Hornblende most common
• MICA Group- Si O in sheets
• Biotite
• Muscovite
• CALCITE- CaCO3

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Properties of Minerals

• Color
• Not always reliable (Olivine, green Flourite,
  yellow, purple, green)
• Ferromagnesian minerals green or black
• Streak- powdered form
• Luster- reflectance of light
• Metallic
• Nonmetallic
• Vitreous or Glassy
• Earthy

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Properties of Minerals

• Hardness- resistance to scratching
• Mohs Hardness Scale
• Fingernail 2.5
• Penny 3.5
• Knife/Glass 5.5
• Streak Plate 6.5
• Crystal Form
• Law of Constancy of Interfacial Angles

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Properties of Minerals

• Cleavage
• Quality (poor, good, perfect)
• Number of directions
• One- e.g. Mica
• Two at right angles- e.g. Feldspar, Pyroxene
• Two not at right angles- e.g. Amphibole
• Three at right angles (cubic)- e.g. Halite
• Three not at right angles (rhombohedral)- e.g.
  calcite
• Four (Flourite) or six (Sphalerite)- not common

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Properties of Minerals

• Fracture
• Absence of cleavage
• Irregular fracture
• Conchoidal fracture- Quartz
• Density
• Specific Gravity
• Some unusual properties
• Striations, Magnetism, Taste, Odor, Double
  refraction

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Chemical tests

• Reaction with HCl
• Calcite effervesces

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ROCK CYCLE

• Equilibrium
• Interrelationships between
• igneous rocks
• sediment
• sedimentary rocks
• metamorphic rocks
• weathering and erosion
• Plate Tectonic Example

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ROCK CYCLE

• Equilibrium
• Interrelationships between
• igneous rocks
• sediment
• sedimentary rocks
• metamorphic rocks
• weathering and erosion
• Plate Tectonic Example

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