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MINERALSMINERALS
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Minerals Video
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The solid part of the Earth is made out of
rocks.
The rocks are made out of minerals.
Around 4,000 different minerals
MINERALS
Naturally occurring, inorganic solid, that hasits own specific
chemical composition and
structure (crystalline)
Minerals are made out of ELEMENTS.
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ELEMENT- Contains only one kind of atom.
Ninety-two elements found in nature
Others have been produced artificially
Atomic number - number of positively
charged protons in nucleus and electrons
outside the nucleus
CCarbon
12.011
6ATOMIC NUMBER
Number on Chart
ATOMIC SYMBOLAbbreviation
ELEMENT NAME
ATOMIC MASSNumber of Protons added to
the number of Electrons
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Some minerals are made out of only one
element.EXAMPLE: SULFUR (S)
GOLD (Au)
GRAPHITE (C)DIAMOND (C)
Most minerals are made out of compounds(combinations of
elements).
EXAMPLE: QUARTZ (SiO2)HALITE (NaCl)
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MOST ABUNDANT
ELEMENTS IN MINERALS
MOST ABUNDANT
ELEMENTS IN MINERALS
***See Earth Science Reference Tables***
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MINERAL
STRUCTURE
MINERAL
STRUCTURE
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Crust - most abundant elements are oxygen
and silicon
Therefore, the most abundant group of
minerals, THE SILICATES, contain oxygen
and silicon.
The silicate minerals chemical structure is in
the form of a TETRAHEDRON.
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OXYGEN
ATOM OXYGEN
ATOM
OXYGEN
ATOMOXYGEN
ATOM
SILICONATOM
TETRAHEDRON
Four oxygen atoms at four corners around onesilicon atom at
center
Different silicate minerals bond, or share
oxygen atoms different ways
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MINERALPROPERTIESMINERALPROPERTIES
Mineral have physical and chemical
characteristics, make identifiable
Elements in mineral and how they are
arranged tell properties
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1. CRYSTAL FORM-
How strongly bonded and how arrangeddetermines the shape of
individual mineral
EXAMPLE: Two silicate minerals:
MICA- forms thin sheets.
QUARTZ- forms six sided
crystals.
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2. CLEAVAGE / FRACTURE-
Minerals have a tendency to cleave or splitsmoothly if have weak
bonds
If there are no weak bonds than the crystal
fractures or breaks
CLEAVAGE - flat parallel sides.
FRACTURE - jagged sides.
EXAMPLES: Mica - cleavage
Halite - cleavage
Quartz - fracture
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Cleavage Rock showing Fracture
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3. COLOR- determined by elements present
Color alone should not be used for mineral
identification.
One mineral may come in many different
colors.
EXAMPLE: QUARTZ- White, red, green, etc.
Many different minerals may be the same
color
EXAMPLE: QUARTZ, CALCITE, HALITE
are white
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Quartz Different Colors
Quartz, Halite, Calcite All white minerals
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4. HARDNESS- minerals resistance to being
scratched.
#1 the softest is Talc ...
#10 the hardest is Diamond.
b) Hardness Test
a) THE MOHS HARDNESS SCALE:
A list of minerals and their known hardness
Scratches material = harder
Does not scratch = softer
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Hardness tests:
Fingernail: ... hardness 2.5
Copper penny: . hardness 3.5
Iron nail: . hardness 4.5
Glass plate: . hardness 5.5
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5. STREAK-
The color of the powder of a mineralIt is determined by
scratching a mineral on a
hard white porcelain plate.
Streak gives the true color, better than color
of mineral
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6. LUSTER- The way the minerals surface
reflects light
There are two major groups:
METALLIC: Minerals that look like silver orgold
EXAMPLE: GALENA is silver
PYRITE is gold
NONMETALLIC: Minerals that look like
glassy, dull, pearly, earthy, etc.
EXAMPLE: QUARTZ is glassy
TALC is dull
MUCOVITE MICA is pearly
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7. SPECIFIC GRAVITY-
A comparison of a minerals density to the
density of water 1g/cm3
8. SPECIAL PROPERTIES-
CALCITE bubbles when acid touches it
MAGNETITE is magnetic
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