Minerals:
Building Blocks of
Rocks
~Chapter 5~
^_^
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
Composition and
structure of minerals
Atoms
• Smallest particles of matter
• Elements
• Basic building blocks of minerals
• Over 100 are known
Periodic table of the Elements
How atoms are
constructed
Nucleus – central part of an atom that
contains
• Protons – positive electrical charges
• Neutrons – neutral electrical charges
• Have all the characteristics of an elements
Energy levels, or shells
• Surround nucleus
• Contain electrons – negative electrical
charges
Simplified view of the atom
How atoms are
constructed
Atomic number is the number of
protons in an atom's nucleus
Bonding of atoms
• Forms a compound with two or more
elements
• Ions are atoms that gain or lose electrons
Isotopes
• Have varying number of neutrons
How atoms are
constructed
Isotopes
• Have different mass numbers – the sum of
the neutrons plus protons
• Many isotopes are radioactive and emit
energy and particles
Minerals
Physical properties of minerals
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Crystal form
Luster
Color
Streak
Hardness
Cleavage
Fracture
Other properties (taste, smell, elasticity, malleability, feel,
magnetism, double refraction)
Crystal Form
Luster
Cleavage
Streak
Hardness
Cleavage
Fracture
Other PropertiesCrystal Form
The mineral quartz often
exhibits good crystal form
Pyrite (fool’s gold)
displays metallic luster
Three examples of perfect
cleavage – fluorite, halite,
and calcite
Conchoidal fracture
Minerals
Physical properties of minerals
• Other properties
• Feel
• Magnetism
• Double Refraction
• Reaction to hydrochloric acid
Minerals
A few dozen minerals are called the rockforming minerals
• 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:
• Oxygen (46.6% by weight)
• S ilicon (27.7% by weight)
Minerals
Major Mineral groups
• Rock-forming silicates
• Most common mineral group
• Contain the silicon-oxygen tetrahedron
• Four oxygen atoms surrounding a much
smaller silicon atom
• Feldspars are the most plentiful mineral group
• Crystallize from molten material
Minerals
Mineral groups
• Rock-forming silicates :
• 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
• Rock-forming silicates
• Micas – tetrahedra are arranged in sheets
Biotite and Muscovite
• Feldspars - Blocky
• Two types- Orthoclase and Plagioclase
• Quartz –
Potassium feldspar
Plagioclase
feldspar
Major Mineral groups:
Nonsilicate Mineral Groups:
Oxides
Sulfides
Carbonates
• A major rock-forming group
• Found in the rocks limestone and marble
• Evaporites
• Halite and gypsum are found in sedimentary rocks
• Many have economic value
Native Copper
Some common non-silicate
minerals
Mineral resources
• 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
The Bingham copper
mine in Utah
Formative Mineral Quiz
Directions:
Take out separate piece of paper
and number 1-17
For each slide, identify the
mineral either based on how it
looks or on the clue given.
Correct quiz and record which
ones you need study more!
Concoidal Fracture
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IDENTIFY IT!
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HCL Test (fizzing)
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Double Refraction
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IDENTIFY IT!
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Perfect Cleavage (3 at 90
deg.)- NO THER HINTS!
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Definitely not gold… unless
you’re a fool.
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Fibrous
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MOHS = 1
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Streak Test
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Magnetic… but the streak is
throwing me off
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Uber Magnetic
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Filmy… Flat… White…
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Black. Black starts with B.
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Metallic mineral. Ugly color.
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Looks like Pyrite… but its not
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Speckled. Reacts with Acid
when powdered
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Answer Key
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17.
Quartz (Box 1)
Olivine ( Box 1)
Calcite (Box 1)
Calcite (Box 1)
Azurite ( Box 2)
Halite (Box 3)
Pyrite ( Box 2)
Gypsum ( Box 1 OR 3)
Talc ( Box 3)
Hematite ( Box 2)
Hematite ( Box 2)
Magnetite ( Box 2)
Muscovite ( Box 1)
Biotite ( Box 1)
Limonite ( Box 2)
Chalcopyrite ( Box 2)
Dolomite ( Box 3)