Chapter 2.2
MINERALS
Definition of a Mineral
 Naturally occurring- which means minerals are not
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a man-made substance.
Solid at normal temps on the Earth’s surface- What
about ice? Glaciers?
Orderly Crystal Structure- Some crystals are
microscopic, other are macroscopic.
Definite Chemical Composition- A recipe in specific
proportions, such as H2O, SiO2, NaCl etc.
“Generally” Inorganic- Not from a living source.
Sugar crystals are organic because they come from a
plant. The rules are sometimes vague, because
limestone (CaCO3) comes from living invertebrates,
but is still considered a mineral.
Minerals
Galena (PbS)
Halite, Rock Salt (NaCl)
Fluorite (CaF2)
Muscovite Mica (KAl3Si3O10(OH)2
How do Minerals Form?
 There are four major processes which are
involved in the formation of minerals
 Crystallization from magma- Magma cooling
down to form igneous rocks.
 Precipitation- Water that contains dissolved
minerals evaporates, leaving minerals behind.
 Pressure and Temperature- Example: Coal or
graphite can change into a diamond.
 Hydrothermal- Hot water mixed with minerals
can form chemical reactions.
Mineral Formations
Granite formed by Crystallization of Magma.
Minerals present- Mica, Quartz, Feldspar
Garnet Schist formed by
extreme heat and pressure
Limestone precipitate from a Cavern
Minerals present- Calcite (CaCO3)
Gold in a sample of Quartz formed
by a hydrothermal solution
Minerals Groups
 There are literally thousands of different
minerals found all over the earth.
 Is there an easier way to remember the
minerals and their properties?
 Yes, we can classify them into groups.
 There are 6 different mineral groups based
on their general compositions.
The Silicates
 The Silicates are the most abundant minerals
on the earth.
 Silicates contain the elements silicon and
oxygen.
 Together they form covalent bonds to make a
silicon-oxygen tetrahedron.
 These are a few of the most common
silicates: Quartz, Feldspar, Talc, and Mica.
The Silicates
Silicates are not only abundant, but also very useful. Silicates are used
not only to make glass and ceramics, but also to keep time in watches,
to produce microchips for technology like your cell phones and computers.
Silicates are some of the most widely used minerals on the planet.
The Carbonates
 The second most abundant mineral group.
 They contain the elements carbon, oxygen,
and one or more other metallic elements.
 Calcite and Dolomite are two common
Carbonate minerals. They are found in rocks
like Limestone and Marble.
The Carbonates
The Mineral Calcite
Stalactites and Stalagmites are
made of Carbonates
If you ever taken tums for an upset stomach
you have consumed a carbonate mineral.
The Oxides
 Oxides are minerals that contain oxygen and
one or more other elements, which usually
are metals.
 Some examples of common oxide minerals
include: Corundum (Al2O3), Hematite
(Fe2O3), and Magnetite (Fe3O4)
The Oxides
Rubies and Sapphires are made of Corundum
Plain old rust is made of
the mineral Hematite
If you ever found a rock that is magnetic,
chances are you found magnetite.
Sulfates and Sulfides
 Sulfates and Sulfides are minerals that
contain the element sulfur.
 Sulfides like Gypsum form when mineral rich
waters evaporate.
 Sulfates like Galena and Pyrite form from hot
hydrothermal solutions like hot springs.
Sulfates and Sulfides
Pyrite, fools gold
Galena
Desert rose, Gypsum
Ordinary Gypsum
The Halides
 The Halides are minerals that contain a
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halogen ion plus one or more other elements.
Halogens are elements that are in group 7A of
the periodic table.
Some of the most common elements in
group 7A are fluorine (F) and Chlorine (Cl).
Two common Halite minerals are halite
(NaCl) and Fluorite (CaF2).
Both of these minerals form when mineral
rich water evaporates.
The Halides
Halite, Rock Salt
Green Fluorite
Dry Lake Bed in Death Valley
Filled with Halite
Purple Fluorite
Native Elements
 Native Elements are a group of minerals that
exist in relatively pure form.
 Some common examples of native elements
include gold (Au), silver (Ag), copper (Cu),
sulfur (S), and carbon (C).
 Graphite and diamond are both minerals that
contain the element carbon, but their
properties are very different.
Native Elements
Copper
Gold
Sulfur
Diamond, a form of Carbon