Transcript MINERAL IDENTIFICATION

MINERAL IDENTIFICATION
WHAT IS MINERALOGY?
Mineralogy is the study
of _______________
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ROCK FORMING MINERALS
There are nearly
_________ minerals but
there are only _______
That are at all common.
Elements like gold and
diamond are rare.
COMMON MINERALS
The most common
minerals are _______,
_________, _________,
and ______________
These and others make
up most of the minerals
in the Earth’s crust also
known as __________
__________________
__________________
WHAT IS THE DIFFERENCE BETWEEN A
ROCK AND A MINERAL?
The difference between
a rock and mineral are
the following:
____________________
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HOW ARE MINERALS IDENTIFIED?
Geologists look at the
physical and chemical
properties and simple
tests to help them
identify each mineral.
These are:
a.___________________
b.____________________
c.________________
d.____________________
e. __________________
f.____________________
g.____________________
h.____________________
i_____________________
j.____________________
COLOR
•One of the most
noticeable
characteristics of a
mineral.
•However, it is not the
most reliable.
•The color of the
minerals is sometimes
caused by the presence
of trace elements or
compounds within the
mineral.
QUARTZ
Quartz occurs in a
variety of colors.
These different colors
are the result of
different trace elements
in the quartz samples.
Amethyst and citrine
contain different
amounts of iron
Rose quartz contains
manganese and
titanium
CRYSTAL FORM
•Some minerals form
such distinct crystal
shapes that they are
immediately
recognizable.
•Halite always forms
perfect cubic crystals
•As you have found not
all minerals form
perfect crystal shapes
so, to identify a crystal
solely based on crystal
formation is rare.
LUSTER
Luster is the way ____
____________________
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There are two types of
luster :
__________________
And
__________________
METALLIC LUSTER
________, __________,
___________ ,
_______________
All have shiny surfaces
and reflect light.
However, not all
metallic minerals have
metallic luster
_____________ is a
mineral with a metallic
luster but is not a metal
NONMETALLIC LUSTER
Minerals with nonmetallic
luster , like calcite
Gypsum, sulfur and quartz
do not shine like metals.
Nonmetallic luster are
described as ______,
_________, _________
_________, _________
Differences in luster are due
to the differences in the
___________
_____________ of the
minerals. Identifying
nonmetallic luster maybe a
bit difficult . It is a good
practice to use another
physical characteristic with
luster in identifying a
mineral.
HARDNESS
•One of the most reliable
tests for identifying a
mineral.
•_________is a measure
Of how easily a mineral
can be scratched.
German Geologist
Friedrich Mohs
developed the scale by
which an unknown
mineral’s hardness can
be compared to 10
known minerals.
The ten minerals
selected were the most
easily recognized and
most common in nature
with the exception of
diamond.
THE SCALE
The scale ranges from 1-10
1 is the softest mineral (Talc)
and can be scratched with a
fingernail –
To 10 diamond which can
scratch all the minerals on
the list
A mineral that can be
scratched by your fingernail
has a hardness of 2 or less.
A mineral that cannot be
scratched by your fingernail
and cannot scratch glass has
a hardness value between
2.5 and 5.5
A mineral that can scratch
glass has a hardness value of
5.5 or greater
MATERIALS USED TO CONDUCT THE
HARDNESS TEST
Fingernail - 2.5
Copper penny – 3.5
Iron nail- 4.5
Glass-5.5
Steel file – 6.5
Streak plate - 7
If there is more than
one mineral in the
sample it is a good idea
to test more than one
area of the sample. This
way you can be sure
you are testing the
hardness of the mineral
you are studying.
CLEAVAGE AND FRACTURE
•Atomic arrangement
will also determine how
a mineral will break.
•Minerals break where
atomic bonding is
weak.
•A mineral that splits
relatively easy and
evenly along one or
more flat planes
exhibits ____________
•An example is mica it
breaks in one direction.
It breaks in sheets
because of weak atomic
bonds.
FRACTURE
Quartz breaks unevenly
along jagged edges
because it has tightly
bonded atoms.
Minerals that break
with rough or jagged
edges are said to
_________________
Flint , jasper also
exhibit fracture with
arclike patterns that
resemble a clamshell .
This is a good property
in identfying minerals.
STREAK
A mineral rubbed across an
unglazed plate will
sometimes leave a colored
powered streak on the
surface of the plate.
___________ is the color of
the mineral when it is broken
up into a powder.
The streak of a nonmetallic
mineral is usually
____________.
Streak is most useful when
identifying a metallic
mineral.
Sometimes the streak does
not match the metallic
mineral’s external color
Hematite is a good example
HEMATITE
Hematite that forms
from weathering
(exposed to air and
water) is a rusty red
color and has an earthy
feel.
Hematite that forms
from magma is silver
and metallic in
appearance . Both
however, show a red
streak when tested.
This is another reason
streak cannot be the
sole test.
SPECIAL PROPERTIES
Several minerals exhibit
special properties that
can easily identify them
Calcite (Iceland Spar)
-Double refraction
-Calcite- Effervescence
-Magnetite- Magnetism
-Fluorite/CalciteFluorescence
TEXTURE
Texture describes how a
mineral feels to the
touch.
This is also difficult
because this can be
somewhat subjective
like luster.
Texture of a mineral can
be described as
smooth, ragged,
greasy, or soapy.
SPECIFIC GRAVITY/ DENSITY
Sometimes two
minerals of the same
size have different
weights .
Differences in weight is
the result of differences
in densities.
Density reflects the
atomic mass and
structure of the mineral
Because density is not
dependent on the size
or shape .
Density at times can be
very hard to determine .
SPECIFIC GRAVITY
The most common
measure of density in
minerals is __________
____________________
It is the ratio of the
mass of a substance to
the mass of an equal
volume of water at 4
degrees C.
SUMMARY
The most reliable way
to identify a mineral is
by using a combination
of several test.