Minerals - Part II
7 Major mineral groups
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Nature’s most common building block in rock
forming minerals is the …
Silica Tetrahedra SiO4
1) Silicate Minerals
Quartz is the second
most abundant
mineral on the
earth’s crust
(the most abundant element on the earth’s
crust is therefore oxygen)

Quartz is used for
glass, jewelry and
electronics
Feldspars
Feldspar is the
most abundant
“family” of minerals
on the earth’s crust.
The various feldspar
minerals make up
over 60 percent of the crust.
 (Aluminum ions replace silicon ions)

Feldspars

Feldspar is used for
ceramics (china) and glass

Micas are soft silicates
found in many rocks micas most distinctive
feature is that it has
one cleavage surface
– they are pearly and
‘flake’ easily
Micas
Micas
Micas are used for
electronic insulation

Amphiboles
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– complex
type in the
silica group
where iron
and
magnesium
have
replaced a
silica ion.
Carbonates
Carbonate mineral group is made up of
compounds of one carbon and 3 oxygen atoms
(CO3) joined with various metal ions
Carbonates
react with acid (HCl);
calcite reacts strongly
with acid, other
carbonate minerals
react only mildly with
acid.
Other Carbonate Minerals

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Dolomite =
CaMg(CO3)2
Siderite = FeCO3
Oxides
Metal + oxygen = oxide
 For example:
Hematite = Fe2O3
Franklinite = (Zn,Mn,Fe)2+ (Fe,Mn)3+2O4
Sulfides
Metal + sulfur = sulfide
 For Example:
Pyrite = FeS2
Sulfates
Sulfur + 4 Oxygen
atoms = Sulfate SO4
 For example: Barite
= BaSO4
Halites (Salts)
Compounds of elements and chlorine, fluorine,
iodine or bromine
For example:
table salt = NaCl,
potassium salt = KCl
Native Elements

Elements found uncombined with other elements,
For example:
gold
silver
copper
sulfur
diamond
7 Mineral Groups
(in relative order of abundance)
1.
2.
3.
4.
5.
6.
7.
Silicates – minerals that contain silicon &
oxygen, and usually one more element
Carbonates – contains carbon w/3 oxygen
atoms
Sulfates – contains sulfur w/four oxygen atoms
Halides – compounds of certain elements and
chlorine, fluorine, iodine or bromine
Oxides – compounds of elements and oxygen
(usually rust looking)
Sulfides – compounds of elements and sulfur
Native Elements – elements found
uncombined w/other elements (copper, gold,
etc…)
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Single chain silicates…

End here
Look familiar?
Felspar…
Microcline
Distinguishing
feature:
the ‘laminae’
– little veins
in the mineral
Garnet
Ca3Al2(SiO4)3
Look familiar?
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Hornblende:
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striated appearance
hexagonal crosssection
Dark-dark green to
black
Look familiar?
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Magnetite

magnetic
Look familiar?
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Olivine

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Light to dark green
Really hard (6.5-7)
Look familiar?
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Franklinite
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Stubby metallic
crystals, usually in
calcite
Look familiar?

Zincite
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red
vitreous
orange-yellow streak
Willmenite
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green
strongly fluorescent
green