Download MINERALS

MINERALS
CONCEPT REVIEW
EARTH IS MOSTLY MADE
UP OF ROCK
 ROCKS ARE MADE UP OF
MINERALS
 THERE ARE 3800+
NAMED MINERALS
 MOST ROCKS ARE MADE
OF JUST A FEW OF THESE

CONCEPT REVIEW


ATOMS COMBINE NATURALLY TO
FORM MINERALS
ATOMS BOND IN DIFFERENT WAYS
COVALENT
IONIC
METALLIC
HOW DO WE KNOW IT’S A
MINERAL?
CHARACTERISTICS OF A MINERAL…
MUST:
1. Be naturally occurring
2. Be inorganic (generally)
3. Be a solid
4. Have a definite chemical composition
5. Have a repeating crystal lattice
Naturally Occurring


Mineral must be found in
nature
Not artificially created in the
laboratory
• For example – cubic zirconium
is NOT a mineral since it is
artificial only
• However, halite created in the
lab IS a mineral because it is
also found in nature
Inorganic
Mineral can not be formed from living
things
 Inorganic substances are non-living
(past, present, future)
Exception – calcite is produced by
living sea creatures

Inorganic substances do not contain chains of
carbon atoms (are not carbon based)
Exceptions are Graphite (C) and Diamond (C)

Solid

Minerals cannot be liquids or gases
• For example – water is NOT a mineral,
but glacial ice IS a mineral
Definite Crystal Structure

Highly ordered atomic arrangement
of atoms in regular geometric
patterns
Apatite
Feldspar
Diamond
Quartz
8
Minerals are crystalline
substances
which means that their
atoms or ions are arranged in an orderly
and repetitive manner.
The gemstone opal is not a mineral even
though it contains the same
elements as quartz. Opal does not have
an orderly internal structure.
Repeating Crystal Lattice

Minerals with the
same chemical
composition can
have different
lattices – making
them different
minerals!
• For example –
take a look at
these lattices for
Diamond (C) and
Graphite (C).
Definite Chemical Formula

Minerals are expressed by a specific
chemical formula
-Gold (Au)
-Calcite (CaCO3)
-Quartz (SiO2)
-Pyrite (FeS2)
-Halite (NaCl)
HOW DO MINERALS FORM?
1.
2.
3.
4.
5.
CRYSTALLIZATION OF MAGMA
PRECIPITATION
METAMORPHISM - CHANGES IN
TEMPERATURE AND PRESSURE
CHEMICAL WEATHERING
FROM HYDROTHERMAL
SOLUTIONS
Cooling of Magma
Magma is a
molten “soup” of
minerals

• As it cools,
certain minerals
crystallize at
different
temperatures
• This removes
some elements
from the magma
and changes its
composition
Precipitation

Precipitation here refers to
the formation of a solid from
a liquid
• Can be as simple as
evaporation or a chemical
reaction where two liquids
combine to form a solid
• Calcite, gypsum, and halite
form this way.
Metamorphism

Metamorphism is a change in a mineral
(or rock) brought about by changes in
heat and pressure.
•Increased heat and/or
pressure causes mineral
structure (lattices) to
change – resulting in a new
mineral
•Minerals can be
recrystallized or foliated
(aligned in layers)
Chemical Weathering



Chemical weathering of
minerals occurs at the
surface of the earth in
soils and clays
Chemical reactions
take place and change
the mineral structures
– resulting in a new
mineral
For example –
orthoclase reacts with
acid rain to form
kaolinite
Hydrothermal Solutions
A hydrothermal solution is a hot
water solution containing a variety of
substances
 The temperature of the water allows
a great deal of mixing and reacting
to take place
 Results in numerous
combinations of
substances – forming
many minerals
 Sulfides are often
formed this way

Summary


A mineral is a naturally occurring
solid with a definite chemical formula
and crystal lattice and is generally
inorganic.
Minerals can form in five common
ways – magma cooling, precipitation,
metamorphism, chemical
weathering, and hydrothermal
solutions.