Transcript MINERALS

MINERALS
Chemical
composition of the
Crust
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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
MINERAL vs. ROCK
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ROCK
 An
aggregate of one or more MINERALS
(usually- coal, organic)
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MINERAL
 Solid
 Crystalline-
orderly arrangement of atoms
 Naturally occurring
 Inorganic
 Definite chemical composition
 e.g.
SiO2 for quartz; KAlSi3O8 for
feldspar
Atom & Elements
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Atoms
 Neutral
 Nucleus
 Proton,
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Electron
Ions
 Electrical
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neutron
Charge
Molecule- e.g. water molecule
Chemical activity
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Stable atoms want
 positive
& negative charges balanced
 electron shells full
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Ions- positive (Cations) and negative (Anions)
Bonding
 Ionic
 Covalent
 Metallic
 Van
der Waal’s
Element
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Atomic number
 Number
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of PROTONS
Isotope
 Differing
number of
NEUTRONS
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Atomic weight
 Mass
of PROTONS and
NEUTRONS
Crystallinity
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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
MINERALS
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Crystalline solids
Natural and Inorganic Substances
Definite chemical composition
 Can
be written as a chemical
formula
 Solid solution (within a range)
Important Minerals
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Quartz (most abundant)
FELDSPAR Group
 Potassium
Feldspar - Orthoclase
 Plagioclase Feldspar
 Sodium
(Na) Albite
 Calcium (Ca) Anorthosite
Important Minerals
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PYROXENE Group- Augite most
common
AMPHIBOLE Group- Hornblende
most common
MICA Group- Si + O in sheets
 Biotite
 Muscovite
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CALCITE- CaCO3
Properties of Minerals
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Color
 Not
always reliable (Olivine, green; Flourite,
yellow, purple, green…)
 Ferromagnesian minerals green or black
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Streak- powdered form
Luster- reflectance of light
 Metallic
 Nonmetallic
 Vitreous
 Earthy
or Glassy
Properties of
Minerals
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Hardness- resistance to scratching
Moh’s Hardness Scale
 Fingernail
= 2.5
 Penny = 3.5
 Knife/Glass = 5.5
 Streak Plate= 6.5
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Crystal Form
 Law
of Constancy of Interfacial
Angles
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Cleavage
Properties of
Minerals
 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
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Density
 Specific
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Gravity
Some unusual properties
 Striations,
refraction
Magnetism, Taste, Odor, Double
Chemical tests
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Reaction with HCl
 Calcite
effervesces
ROCK CYCLE
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Equilibrium
Interrelationships between
 igneous
rocks
 sediment
 sedimentary rocks
 metamorphic rocks
 weathering and erosion
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Plate Tectonic Example
ROCK CYCLE
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Equilibrium
Interrelationships between
 igneous
rocks
 sediment
 sedimentary rocks
 metamorphic rocks
 weathering and erosion
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Plate Tectonic Example