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Geochemistry
Periodic Table of the Elements
Chemical
Compound:
Sodium Chloride
(NaCl)
Mineral: Halite
(NaCl)
What is a Mineral?
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Naturally occurring
Inorganic
Crystalline solid
Definite chemical composition
Diamond
Silica Tetrahedron
Quartz
silicon dioxide
(SiO2)
Sheet silicates
(e.g. micas)
Unordered atoms
(glass)
Feldspars
Micas
Rock-forming silicates
Halite
Gold
Pyrite
Gypsum
Calcite
Hematite
Physical Properties of Minerals
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Cleavage
Breakage along planes of weakness in the crystal structure.
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Color
Visible light spectrum radiation reflected from a mineral.
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Crystal Form
Geometric shape of a crystal.
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Fracture
Breakage not along planes of weakness in the crystral structure.
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Hardness
Resistance to scratching or abrasion.
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Luster
Character of the light reflected by a mineral.
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Magnetism
Magnetic attraction.
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Reaction to HCl Chemical interaction of hydrochloric acid and calcium carbonate
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Specific Gravity Ratio of the mass of a mineral to that of an equal volume of water.
(density)
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Streak
Color of the mineral when it is powdered.
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Fluorescence
Colour of mineral in ultraviolet light
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Radioactivity
Measured by scintillometer or geiger counter
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Diaphaneity
How light is transmitted through the mineral
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Conductivity
Does the mineral conduct an electrical current?
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Taste
1 = talc
10 =
diamond
Hardness (Mohs Scale)
Streak
Colour
Habit &
Lustre
Cleavage &
Diaphaneity
What is a Rock ?
•! Naturally formed
•! Consolidated material
•! Composed of grains / crystals of one or
more minerals
Types of Rocks
•! Igneous (formed from solidification of molten
rock)
•! Sedimentary (formed from:
–! the lithification of any sediment, or
–! precipitation from solution on Earth
s surface,
or
–! consolidation of the remains of plants and
animals
•! Metamorphic (formed from changes induced
by changes in pressure and/or temperature)
Extr usive (volcanic)
Intr usive (plutonic)
Igneous Rocks
Volcanic
Plutonic
Erosion and uplift