Transcript Lecture Outlines PowerPoint Chapter 2 Earth Science 11e Tarbuck/Lutgens © 2006 Pearson Prentice Hall EARTH SCIENCE, 11E Minerals: Building Blocks of Rocks Chapter 2 MINERALS: THE BUILDING BLOCKS OF ROCKS  Definition.

Lecture Outlines
PowerPoint
Chapter 2
Earth Science 11e
Tarbuck/Lutgens
© 2006 Pearson Prentice Hall
EARTH SCIENCE, 11E
Minerals: Building Blocks of Rocks
Chapter 2
MINERALS: THE BUILDING
BLOCKS OF ROCKS

Definition of a mineral
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
Natural
Inorganic
Solid
Possess an orderly internal structure of atoms
Have a definite chemical composition
Mineraloid - lacks an orderly internal structure
COMPOSITION AND
STRUCTURE OF MINERALS
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Elements
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
Basic building blocks of minerals
Over 100 are known
Atoms
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Smallest particles of matter
Have all the characteristics of an element
PERIODIC TABLE OF THE ELEMENTS
Figure 2.4
HOW ATOMS ARE CONSTRUCTED

Nucleus – central part of an atom that contains
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
Protons – positive electrical charges
Neutrons – neutral electrical charges
Energy levels, or shells
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Surround nucleus
Contain electrons – negative electrical charges
SIMPLIFIED VIEW OF THE ATOM
Figure 2.5
HOW ATOMS ARE CONSTRUCTED
Atomic number is the number of protons in an
atom's nucleus
 Bonding of atoms

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
Forms a compound with two or more elements
Ions are atoms that gain or lose electrons
Isotopes
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Have varying number of neutrons
HOW ATOMS ARE CONSTRUCTED

Isotopes
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Have different mass numbers – the sum of the
neutrons plus protons
Many isotopes are radioactive and emit energy and
particles
QUIZ BREAK
MINERALS

Physical properties of minerals
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Crystal form
Luster
Color
Streak
Hardness
Cleavage
THE MINERAL QUARTZ OFTEN
EXHIBITS GOOD CRYSTAL FORM
PYRITE (FOOL’S GOLD)
DISPLAYS METALLIC LUSTER
Figure 2.10
Mohs scale
of hardness
Figure 2.12
THREE EXAMPLES OF PERFECT
CLEAVAGE – FLUORITE, HALITE,
AND CALCITE
MINERALS

Physical properties of minerals
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Fracture
Specific gravity
Other properties
 Taste
 Smell
 Elasticity
 Malleability
CONCHOIDAL FRACTURE
Figure 2.15
MINERALS

Physical properties of minerals
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Other properties
 Feel
 Magnetism
 Double
Refraction
 Reaction to hydrochloric acid
QUIZ BREAK
MINERALS

A few dozen minerals are called the rockforming minerals
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The eight elements that compose most rockforming minerals are oxygen (O), silicon (Si),
aluminum (Al), iron (Fe), calcium (Ca), sodium (Na),
potassium (K), and magnesium (Mg)
Most abundant atoms in Earth's crust are oxygen
(46.6% by weight) and silicon (27.7% by weight)
COMPOSITION OF CONTINENTAL
CRUST
Figure 2.16
MINERALS

Mineral groups
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Rock-forming silicates
 Most
common mineral group
 Contain the silicon-oxygen tetrahedron (molecule)
• Four oxygen atoms surrounding a much smaller
silicon atom
• Combines with other atoms to form the various
silicate structures
THE SILICATE (SIO4)-4 MOLECULE
Figure 2.17
MINERALS

Mineral groups
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Rock-forming silicates
 Groups
based upon tetrahedral arrangement
• Olivine – independent tetrahedra
• Pyroxene group – tetrahedra are arranged in chains
• Amphibole group – tetrahedra are arranged in double
chains
HORNBLENDE – A MEMBER OF
THE AMPHIBOLE GROUP
MINERALS

Mineral groups
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Rock-forming silicates
 Groups
based upon tetrahedral arrangement
• Micas – tetrahedra are arranged in sheets
• Two types of mica are biotite (dark) and muscovite
(light)
• Feldspars - Three-dimensional network of tetrahedra
MINERALS

Mineral groups
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Rock-forming silicates
 Groups
based upon tetrahedral arrangement
• Feldspars
• Two types of feldspar are Orthoclase and
Plagioclase
• Quartz – three-dimensional network of tetrahedra
POTASSIUM FELDSPAR
PLAGIOCLASE FELDSPAR
MINERALS

Mineral groups
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Rock-forming silicates
 Feldspars
are the most plentiful mineral group
 Crystallize from molten material
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Nonsilicate minerals
 Major
groups
• Oxides
• Sulfides
MINERALS

Mineral groups
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Nonsilicate minerals
 Major
groups
• Sulfates
• Carbonates
• “Native” elements
QUIZ BREAK
NATIVE COPPER
MINERALS

Mineral groups
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Nonsilicate minerals
 Carbonates
A major rock-forming group
• Found in the rocks limestone and marble
 Halite and gypsum are found in sedimentary rocks
 Many have economic value
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MINERALS
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Mineral resources
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Reserves are already identified deposits
Ores are useful metallic minerals that can be mined
at a profit
Economic factors may change and influence a
resource
AN UNDERGROUND HALITE (SALT) MINE
END OF CHAPTER 2