Minerals
A mineral is a naturally occurring,
inorganic solid that has a crystal
structure and a definite chemical
composition.
4,000 Different Minerals
• Share 4 Characteristics
– All minerals are formed in a natural process
– Minerals are inorganic
– Every mineral is an element or a compound
with a definite chemical composition
– Minerals are crystalline solids
A. Naturally occurring
• A mineral has to be
found on the earth's
surface or dug up
out of the crust, not
made in a lab
somewhere by
people.
• Examples of manmade objects are
bricks, cement,
and glass
B. Inorganic
• This means that
they do not come
from living things.
Since coal forms naturally in the crust
and from living things it is not a mineral
C. Solid
• Solids are
substances that
have a definite
shape and a
definite volume.
• The particles are
tightly packed and
can not flow freely.
D. Crystal structure
• The atoms that
minerals are made
of are connected to
each other in a
pattern.
• This pattern is
called its crystal
structure.
• The flat sides form
faces
E. Definite Chemical
Composition
• This means that there is
a specific chemical
formula for each
mineral.
• The mineral pyrite is
made of 1 atom of iron
for every 2 atoms of
sulfur. (FeS2)
• Pyrite will have the
same chemical formula
regardless of where it is
found.
Identifying
Minerals
Each mineral has its own
characteristics or properties
that help you identify it.
Identifying Minerals
a. Hardness
• Hardness is one of the best
clues to identify a mineral.
• Mohs hardness scale ranks
ten minerals from softest to
hardest.
• A mineral will scratch any
mineral softer than itself.
Identifying Minerals
B. Color
malachite
• Color is a physical
property that is easily
observed, however
not many minerals
have distinct colors.
• Malachite is always
green
• Azurite is always blue
Identifying Minerals
C. STREAK
• Streak refers to the
color of a mineral’s
powder.
• Testing a mineral’s
streak is done on an
unglazed piece of tile.
• Although a mineral’s
color may change its
streak color does not.
Identifying Minerals
D. Luster
Tourmanline has a
vitreous (glassy) luster.
• Luster is another
simple test for
determining a mineral.
• Luster refers to how a
mineral reflects light.
• Metals are often shiny
other minerals may be
glassy,waxy or pearly.
Identifying Minerals
E. Density
• The density of a
mineral always
remains the
same.
• Density
measures the
“heaviness” of an
object.
Identifying Minerals
F. Crystal structure
• Each mineral has a
particular crystal structure.
• There are 6 groups bases
on the number and angle
of the crystal faces.
• If a crystal grows in an
open space it produces
perfectly shaped crystals,
however if it grows in a
tight space the crystal are
often incomplete.
Identifying Minerals
G. how it breaks
Calcite has
cleavage
Copper will
fracture
• The way a mineral
breaks apart also can
help identify it.
• If it splits easily along
flat surfaces it has a
property called
cleavage.
• However if it does not
break evenly it has a
characteristic type of
fracture.
How do minerals form?
• In general minerals can form in two ways:
through crystallization of melted
materials, and through crystallization of
materials dissolved in water.
• Magma that cools at a slow rate will
produce large crystals while magma or
lava that cools rapidly will produce small
crystals.
• Minerals are the source of
metals, gemstones, and other
materials used to make many
products.
Gemstones
• Gemstones are hard,
colorful and have a
brilliant or glassy
luster.
• Gemstones are
valued for their color,
luster and durability.
• Once cut a gemstone
is referred to as a
gem.
Metals
• Metals are useful
because they can be
stretched into wire or
hammered into
sheets.
• Metal is use in
making tool framing
buildings and even
the filament in a light
bulb.
Other uses
• Some minerals are
used in foods,
medicines, fertilizers
and other building
materials.