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Chapter 2 Lecture
Earth Science
Fourteenth Edition
Matter and
Minerals
Jennifer Mangan
James Madison University
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Minerals: 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
• Rock – any naturally occurring solid mass of mineral
or mineral-like matter
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Rocks are Aggregates of Minerals
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Atoms: Building Blocks of Minerals
• Atoms
– Smallest particles of matter
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Atomic Structure
• Nucleus – central part of an atom that contains
– Protons – positive electrical charges
– Neutrons – neutral electrical charges
• Electron shells
– Surround nucleus
– Contain electrons – negative electrical charges
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Atomic Structure
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Atoms
• Atomic number
– Number of protons in an atom’s nucleus.
• Ions
– Positively or negatively charged atoms due to electron
gain or loss
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Composition and Structure of Minerals
• Elements
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Basic building blocks of minerals
Over 100 are known
Defined by their number of protons
Groups of the same type of atoms
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Periodic table of the elements
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Atomic Bonding
• Valence shell
– An atom’s outermost shell
• Octet rule
– Atoms gain, lose, or share electrons until their valence
shells have 8 electrons
• Chemical bond
– Transfer or sharing of electrons to achieve full valence
shell
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Atomic Bonding
• Ionic bond
– Atoms bond together when oppositely charged ions attract
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Atomic Bonding
• Covalent bond
– Sharing of a pair of electrons between atoms
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Atomic Bonding
• Metallic bond
– Packed metal atoms have valence electrons free to
move throughout the structure.
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Minerals
• Physical properties of minerals
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Habit – common crystal shape
Luster – appearance in reflected light
Color
Streak – color of mineral in powdered form
Hardness – ability to resist scratching or abrasion
Cleavage – tendency to break along planes of weak
bonding
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Metallic Luster: Galena
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Color
• Color can be unreliable due to variations.
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Streak
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Crystal Shape, or Habit: Pyrite
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Hardness: Mohs Scale
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Cleavage: Micas
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Minerals
• Physical properties of minerals
– Fracture – random pattern of breakage
– Specific gravity – mineral density
– Tenacity – resistance to cutting, breaking, bending, and
deformation
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Conchoidal fracture
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Minerals
• Other properties
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Taste
Smell
Elasticity
Malleability
Double refraction
Magnetism
Feel
Reaction with hydrochloric acid
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Mineral Groups
• Rock-forming minerals
– Only a few dozen
– Most abundant atoms in Earth’s crust are oxygen (46.6%
by weight) and silicon (27.7% by weight)
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Mineral Groups
• Eight elements compose most rock-forming
minerals:
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oxygen (O),
silicon (Si),
aluminum (Al)
iron (Fe)
calcium (Ca)
sodium (Na)
potassium (K)
magnesium (Mg)
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Composition of Continental Crust
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Mineral Groups
• Rock-forming silicates
– Most common mineral group
– Contain the silicon-oxygen
tetrahedron
• Four oxygen atoms
surrounding a much smaller
silicon atom
• Combines with other atoms
to form the various silicate
structures
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Mineral Groups
• 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
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Hornblende: An Amphibole
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Mineral Groups
• 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
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Mineral Groups
• Rock-forming silicates
– Groups based upon tetrahedral arrangement
• Feldspars – most abundant group of minerals in Earth’s crust
• Quartz – three-dimensional network of tetrahedra
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Potassium feldspar
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Rose Quartz
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Mineral Groups
• Nonsilicate minerals – major groups
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Oxides
Sulfides
Carbonates
Halides
Native elements
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Common Nonsilicate Mineral Groups
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Minerals
• Mineral groups
– 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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Natural Resources
• Renewable
– Can be replenished in relatively short time spans
• Corn, wind, water, etc.
• Nonrenewable
– Earth has fixed quantities
• Oil, aluminum, natural gas, coal
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Natural Resources
• Mineral resources
– Mineral resources are occurrences of useful minerals that
will eventually be extracted
– Ore deposits are concentrations of metallic minerals that
can be mined at a profit
– Economic factors may change and influence a resource
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Copper Mining
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