Filling a mineral identification charts

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Attached is the file which you will find the tables 1 and 2
In table 1, I just need you to fill the table with the correct properties for each mineral. Please list, color, luster, hardness, fracture/cleavage, streak color and any other characteristics in the table below for each mineral. Some minerals may not have other characteristics, in that case, put “N/A” in the box.In table 2, I need you to find out what each mineral is used for, list two uses for each.

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GLY 108 – Plate Tectonics: The Active Earth
Lab 1: Minerals
Objectives
1. Appreciate the fundamental distinction between minerals and rocks.
2. Learn the basic physical properties and the process by which minerals are identified.
3. Recognize a few common and economically important minerals on the basis of these physical
properties.
What is a Mineral?
Minerals are naturally occurring, usually inorganic, solids consisting of either a single elements or
chemical compounds, which have a definite chemical composition and a systematic internal
arrangement to their atoms. Minerals are the basic building blocks of the solid Earth. Look at this
definition closely and let’s examine several of these points:
1. A mineral must be natural occurring. This means for any material to be considered a mineral it
must be formed by natural processes; this excludes any man-made materials.
2. A mineral is typically inorganic, meaning that it is not composed of biologically formed carbon
based compounds. This excludes such materials as wood, peat, coal, etc.
3. A mineral must be a solid, i.e., it is not a liquid or gas.
4. A mineral possesses a restricted chemical composition, which can be expressed by a chemical
formula. This does not imply that all minerals possess a single, unique chemical composition,
some do. Others vary their chemical composition over some predictable range.
5. A mineral must be crystalline. This means a mineral possesses a specific crystal structure (an
orderly internal arrangement to the atoms making up the mineral). This excludes materials that
are amorphous in character, materials such as volcanic glass.
Physical Properties of Minerals
As a consequence of its chemical composition and crystallographic structure, each mineral can ideally
be identified by its own individual set of diagnostic properties. These readily observable, mostly
physical properties, include the following:
A. Color for a mineral depends on the wavelength of light reflected off its surface. Some minerals
have a very consistent color that serves as a diagnostic property. The mineral azurite, for example,
is always blue in color; likewise a fresh piece of pyrite always has a brassy yellow color. The color
of other minerals varies widely (ex. quartz can be clear pink, white, violet, brown, etc.). Note:
color is a property one should use with great care when identifying a mineral; it can be seriously
misleading.
B. Luster can be defined as the way light reflects off the surface of a mineral. This should NOT be
confused with a mineral’s color. Two types of luster are recognized: Metallic and Nonmetallic.
1. Metallic Luster is a type of luster commonly seen associated with opaque minerals (minerals
which do not transmit light). These tend to reflect light in such a way that they resemble a
piece of metal such as steel, brass or gold, ex. galena, pyrite.
2. Nonmetallic Luster is generally seen in transparent to translucent minerals (minerals which are
able to transmit light). Objects with a nonmetallic luster may be shiny like glass or dull like
clay or dirt. The point is that they do not look anything like a piece of metal. Examples of a
nonmetallic luster include the following:
a. A vitreous or glassy luster reflects light like a piece of broken glass, ex. quartz, feldspar.
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b. A silky luster has an appearance similar to fine silk or satin, ex. satinspar gypsum, asbestos.
c. A waxy luster has a luster resembling that of wax from a candle, ex. chalcedony, chert.
d. A dull or earthy luster seems to resemble to a clod of dirt, ex. limonite, kaolinite.
C. Streak is the color of the mineral when powdered. We test the streak of a mineral by drawing the
mineral firmly across an unglazed porcelain tile (a streak plate) leaving a powdered streak behind.
This may seem pointless. If a mineral is bright silver, won’t its streak be a silver gray color? Well,
not always. Sometimes the powdered form of the mineral may have a significantly different color,
and this color can be a distinctive property. The streak of a mineral is actually a more reliable
diagnostic property than its color. Minerals harder than the streak plate can actually scratch it. In
many instances this observation can be quite helpful in the mineral’s identification.
D. Hardness is the resistance a mineral offers to being scratched
(abraded). A mineral’s hardness is customarily measured
against a scale that ranges from 1 to 10, with 1 being the
softest mineral known (talc) and 10 the hardest mineral
(diamond). This scale, called “Mohs Scale of Hardness,”
was named after the Austrian mineralogist who first
suggested it (Friedrich Mohs, 1773-1839). Rubbing or
scratching the mineral in question against another material of
known hardness determines a mineral’s hardness. The set of
minerals suggested by Friedrich Mohs for testing a mineral’s
hardness is listed to your right. For practical reasons geologists commonly use other materials for
testing hardness. For example, your fingernail has a hardness ≈ 2.5, a copper penny (minted before
1981) ≈ 3.5, a steel nail ≈ 5.0, a glass plate ≈ 5.5, a streak plate ≈ 6.5.
E. Crystal Form is the geometric shape minerals acquire whenever they are allowed to grow in an
unrestricted environment. As previously mentioned, all minerals have an orderly internal
arrangement to their atoms. When are allowed to grow or develop freely minerals grow into
regular geometric shapes such as cubes, hexagonal crystals, bipyramids, tablets, etc. These shapes
can be unique to each mineral and reflect the internal atomic structure of the mineral.
F. Cleavage and Fracture are terms that refer to the way a mineral breaks.
1. Fracture is a break that is non-planar, sometimes highly uneven or irregular. Fracture is
related to the atomic structure of a mineral, occurring when the chemical bonds within the
crystal are more or less of equal strength in all directions. Some minerals e.g., quartz display a
conchoidal fracture which is scoop shaped and smooth, like that of piece of broken glass.
2. Cleavage is the tendency of a mineral to break along a smooth, planar (flat) surface in a certain
direction. Cleavage is also related to the internal atomic structure of a mineral and represents
planes of weak chemical bonding between layers of atoms. This may or may not be present in a
mineral. One way to recognize a cleavage face is to hold the mineral up to the light; sunlight
because of the parallel nature of its rays, works best. Light reflects brightly off a smooth, flat
cleavage face, a fractured surface tends to appear dull. All flat surfaces that are parallel to one
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another, even very tiny ones, express the same cleavage direction in the mineral. The number
of different, intersecting cleavage planes is an important identifying characteristic of a mineral.
In identifying these different cleavage planes, it is also quite helpful to note the angle between
them. For example, the mineral halite displays a 90˚ angle between each of it three cleavage
directions. Calcite, on the other hand, shows a 60˚ or 120˚ angular relationship between each of
its three cleavage planes. By counting the number of different cleavage planes in a mineral, we
can place them into five groups.
1- direction of cleavage. This particular type of cleavage is sometimes called basal cleavage.
ex. Micas such as Muscovite and Biotite.
2- directions of cleavage. ex. both Feldspar and Pyroxene display a 90° angle between each of
their cleavage planes. ex. Amphibole has a 120° angle between its cleavage planes. This type
of cleavage is commonly referred to as prismatic cleavage.
3- directions of cleavage, ex. Halite shows a 90° angle between cleavages, this type of
cleavage, for obvious reasons, is called cubic cleavage. ex. Calcite has approximately a 60°
or 120° angle between its cleavage planes. Because of its resemblance to a geometric form
called a rhombohedron, this type of cleavage is called rhombohedral cleavage.
4- directions of cleavage, ex. Fluorite. This particular type of cleavage is commonly called
octahedral cleavage. This is because when correctly cleaved, it produces a cool looking 8sided geometric shape called an octahedron (a shape similar to a double pyramid).
6- directions of cleavage, ex. Sphalerite. The shape that can sometimes be produced by this
particular type of cleavage resembles a geometric form called a dodecahedron (12-sided).
For this reason this type of cleavage has come to be known as dodecahedral cleavage.
G. Reaction in Acid can occur in certain minerals whenever a drop or two of dilute hydrochloric acid
(HCl) is applied to their surface. Calcite for example will bubble or fizz profusely whenever a drop
of HCl comes in contact with the mineral. Dolomite, on the other hand, will react weakly to acid
only if it is first scratch or powdered.
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H. Specific Gravity is defined as the weight of a substance in air ÷ the weight of an equal volume of
water. When we compare the specific gravity of two minerals, we are basically comparing the
relative weights of two minerals that are of equal size. In a very generally way, we rate minerals as
having either a high or a low specific gravity (sp. gr.). Metallic minerals tend to have a higher
specific gravity than nonmetallic minerals. That is to say, they tend to weigh more when compared
to nonmetal minerals of similarly size. It should be pointed out, however, that there are several
important exceptions to this general rule (see examples below).
1. Minerals with a Metallic Luster:
High specific gravity: Sphalerite: sp. gr. = 3.9-4.1; Pyrite: sp. gr. = 5.0; Galena: sp. gr. = 7.4-7.6
* Exception: Graphite is a mineral with a metallic luster that has a low sp. gr. = 2.2
2. Minerals with a Nonmetallic Luster:
Low specific gravity: Halite: sp. gr. = 2.2; Quartz: sp. gr. = 2.65; K-Feldspar: sp. gr. = 2.6
* Exception: Barite is a mineral with a nonmetallic luster that has a high sp. gr. = 4.5
I. Magnetism is the ability of a mineral to be attracted by a magnet; ex. magnetite is a metallic, black
colored iron oxide (Fe3O4) that is strongly magnetic. In fact good specimens of magnetite are able
to pick up small metallic objects such as paperclips or small nails.
J. Striations are closely spaced fine lines that may be present on the cleavage surface or the crystal
face of certain minerals. These look like straight, closely spaced grooves. These lines result from
the intergrowth of two crystals called twinning, ex. plagioclase.
K. Taste and Smell are several other properties that can be observed in some minerals. For example,
if you moisten your finger and rub it across the surface of a piece of halite you will notice a
distinctive salty taste. Others minerals may have a distinct smell particularly when scratched across
a streak plate, ex. sphalerite has the smell of “rotten eggs” when streaked; kaolinite will have an
earthy smell when moistened.
L. Feel the mineral by rubbing your fingers over its surface. Some minerals will have a distinctive
feel or texture when this is done. The minerals talc and graphite for example, are extremely soft
and will feel soapy or slippery to the touch.
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MINERAL IDENTIFICATION KEY
Pink (salmon), white, gray color; 2-D cleavage at 90°; Dull
Shows
to glassy luster; H = 6; sp. gr. = 2.6
Lt.
gray to white; 2-D cleavage at 90°; cleavage surfaces
cleavage
may shows fine striations; Dull to glassy luster; H = 6
(Hard)
Can
scratch a
glass plate
Nonmetallic
light color
Clear; Translucent to transparent; Glassy luster; Crystals
common (6-sided); Irregular fracture; H = 7; sp. gr. = 2.6
Milky white color; Glassy to waxy luster; Irregular fracture;
H = 7; a type of crystalline quartz
Pink color; Glassy luster; Irregular fracture; H = 7;
a type of crystalline quartz
Violet to purple color; Glassy luster; Irregular fracture;
No
cleavage A type of crystalline quartz
White, yellow, gray, brown, etc.; Dull to waxy luster; H: 7;
Irregular to conchoidal fracture; type of microcrystalline qtz.
Similar to description of chert above, except variegated
banded colors, no cleavage, no streak; dull to waxy luster
Shades of green to black; Occurs as small sand-sized grains;
Transparent to translucent, Glassy luster; H = 6.5-7
Colorless to white, etc.; 3-D cleavage, planes at 90°;
Salty taste; Soluble in water; H= 2.5
Usually white, pale yellow, or colorless; 3-D cleavage,
planes at ≈ 75°; Effervesces in dilute acid; H= 3
Color variable: white, pink or gray; 3-D cleavage planes at
≈ 75°, Fizzes in acid only when 1st powdered; H= 3.5
Shows Colorless (clear) to lt. yellow or lt. brown; 1-D cleavage;
cleavage Occurs in thin flexible sheets; H = 2.5
Clear to white; scratches easily with fingernail, H = 2;
1-D cleavage good; poor in 2 other directions (Selenite)
(Soft)
Green to white; Greasy feel; 1-D cleavage; Very soft,
Cannot
Dull to pearly luster; H = 1
scratch a
Color variable: clear, yellow, green violet; Grows in cubic
glass plate
crystals; Transparent; 4-D cleavage; Glassy luster; H = 4
K-Feldspar
(KAlSi3O8)
Na-Plagioclase
(NaAlSi3O8)
Rock Crystal
Quartz (SiO2)
Milky Quartz
(SiO2)
Rose Quartz
(SiO2)
Amethyst
(SiO2)
Chert
(SiO2)
Agate
(SiO2)
Olivine
((Fe,Mg)2SiO4)
Halite
(NaCl
Calcite
(CaCO3)
Dolomite
(Ca,Mg(CO3)2
Muscovite mica
hydrous K,Al-silicate
Gypsum
(CaSO4*2H2O)
Talc
(hydrous Mg-silicate)
Fluorite
(CaF2)
Shades of green to white; Irregular fracture; Greasy to silky
Asbestos
luster; Occurs in fibrous to massive forms; H = 2.5-5
(hydrous Mg-silicate)
Pink or white color; Scratches easily with fingernail, H = 2;
Gypsum
Massive or granular (Alabaster); or fibrous (Satin Spar)
(CaSO4*2H2O)
Pale green to white; Smooth, soapy feel; Often appears
Talc
No
cleavage massive; dull to pearly luster; Soft, H = 1
(hydrous Mg-silicate)
Buff to white color; earthy luster; soft & powdery; Earthy
Kaolinite
smell when damp; Absorbs water readily; Soft, H = 1.2
(hydrous Al-silicate)
Sulfur
Yellow color; Resinous luster; No cleavage-uneven fracture;
Yellow to white streak; H = 1.5-2.5; sp. gr . =2.05-2.09
(S)
Hardness = (H)
Specific Gravity = (sp. gr.)
Cleavage = (1-D = 1 direction, 2-D = 2 directions, 3-D = 3 directions, 4-D = 4 directions of cleavage, etc.)
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Light green to green to black color; 2-D cleavage, at 90°;
Dull to glassy luster; Light streak; H = 5-6; sp. gr. = 3.4
Shows Green to black color, 2-D cleavage at 60°/120°; Dull to
cleavage glassy luster; Light greenish streak; H = 5-6; sp. gr. = 3.2
Gray to blue-gray color; 2-D cleavage at 90° with striations;
Glassy to pearly luster w/ blue iridescence; H = 6-6.5
(Hard)
Can
scratch a
glass plate
Nonmetallic
dark color
Gray, brown, blue-grey or red color; 6-sided hexagonal shape
crystals; Dull to glassy luster; H = 9
Red to red-brown color; Glassy luster; Often occurs in 12 or
24-sided crystals, or in fractured pieces; H = 6.5-7.5
Shades of green to yellow; Occurs as small grains;
Transparent to translucent; Glassy luster; H = 6.5-7
No
cleavage Gray to black color; Glassy luster; Irregular fracture; H = 7;
a type of crystalline quartz.
Red to brown color; Dull to waxy luster; Irregular to
conchoidal fracture; H = 7; a type of microcrystalline quartz
Black-brown-gray color; Dull to waxy luster; Irregular to
conchoidal fracture; H = 7; a type of microcrystalline quartz
Shows
cleavage
(Soft)
Cannot
scratch a
glass plate
Black to brown (smoky) color; 1-D cleavage; Breaks into
thin flexible sheets; Glassy luster; H = 2.5-3
Yellow brown to black color; Resinous luster; Streak has a
sulfur smell; 6-D cleavage; H = 3.5-4; High sp. gr. = 4
Red to red-brown color & streak; Earthy luster; occurs in
oölitic or earthy masses; H = 2.5-3.5; sp. gr. = 4-5
No
Yellowish-brown,
brownish-black color; Earthy luster;
cleavage
Yellowish brown to brown streak; H = 1-5; sp. gr. = 3.5
Black, green-black
to dark green streak
Metallic
Luster
Reddish-brown
streak
Yellow, brown or
white streak
Black-dark gray color; Uneven fracture; Magnetic;
Occurs in granular masses; H = 6; High sp. gr. = 5.2
Steel-grey to black color; Smudges fingers; Uneven fracture;
Submetallic luster; Slippery feel; H = 1; Low sp. gr. = 2.2
Pyroxene
(Fe,Mg-silicate)
Amphibole
(Fe,Mg-silicate)
Ca-Plagioclase
(CaAl2Si2O8)
Corundum
(Al2O3)
Garnet
(complex silicate)
Olivine
((Fe,Mg)2SiO4)
Smoky Quartz
(SiO2)
Chert (Jasper)
(SiO2)
Chert (Flint)
(SiO2)
Biotite
(hydrous K,Fe,Mg
aluminum-silicate)
Sphalerite
(ZnS)
Hematite
(Fe2O3)
Limonite
(Fe2O3(OH)6)
Magnetite
(Fe3O4)
Graphite
(C)
Pale brass-yellow; Crystals occur as cubes or in granular
masses; Uneven fracture; H = 6; High sp. gr. = 5.2
Shiny (silver) gray color; 3-D cleavage, planes at 90°;
H = 2.5-3.5: High sp. gr. = 7.6
Pyrite (Fool’s Gold)
Red-brown to steel gray color; Occurring massive or in
granular to platy masses; Uneven fracture; H = 5-6
Hematite (specular)
Yellow-brown, brownish-black color; Metallic to dull luster;
Irregular fracture; H = variable 1-5.5; High sp. gr. = 3.5-4
Yellow-brown to black; Metallic to resinous luster; Streak
has a sulfur smell; 6-D cleavage; H = 3.5-4; High sp. gr. = 4
(FeS2)
Galena
(PbS)
(Fe2O3)
Limonite
(Fe2O3(OH)6)
Sphalerite
(ZnS)
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Key for Identifying Common Minerals
The steps below are commonly used to identify minerals, should you want to identify them in the field.
Step 1
Visually examine a fresh surface of the unknown mineral. Is the luster metallic or is it
nonmetallic? If nonmetallic is the overall color light or dark (dark minerals typically contain
Fe/Mg). If metallic what color streak does it present?
Step 2
In viewing that same fresh surface, determine the hardness of the mineral by scratching it
across a glass plate. If the mineral is harder than a glass plate it will leave a scratch mark on
the glass surface; if the mineral is softer than a glass plate it will not leave a scratch mark on
the surface of the glass. Be sure to wipe the scratch with your finger to confirm it really is a
scratch not a power streak.
Step 3
Next, examine the mineral closely is see if any cleavage planes are present in the specimen.
Once again let’s remember that cleavage is the tendency of a mineral to break along a
smooth, flat surface in a certain direction in the crystal. Recognizing cleavage takes a bit of
practice. To determine the presence of cleavage planes examine the mineral closely under
bright light and look for flat/shiny surfaces. In some minerals (e.g., mica) these can be rather
large and obvious, in other (e.g., pyroxene); they can be quite small and not at all obvious at
first glance. All flat surfaces that are parallel to one another express the same cleavage
direction. Where minerals have more than one cleavage direction, this can be noticed by
observing intersections between flat surfaces. The number of different, intersecting cleavage
planes is an important characteristic of a mineral. Not only is it important to notice the
number of different cleavage planes present in a mineral, but also to notice the angle between
the different planes. If there are two cleavage planes present in a mineral, notice if the angle
between the planes is at 90º (a right angle) or some angle other than 90º. Cleavage or the lack
of it is one of the most important, most diagnostic properties of a mineral.
Step 4
Finally look for any other diagnostic properties you may notice about the mineral. Does the
mineral fizz in acid? Does the mineral attract a magnet? Does the mineral have a distinctive
taste or smell? Notice the feel or the mineral, does it have a slick or greasy feel or is the
surface rough and irregular when you rub your fingers over a fresh surface? Heft the mineral
in your hand. Does it feel particularly heavy or light in weight relative to its size?
Step 5
Using your observations, the instructor provided resources, and the Internet, please list: color,
luster, hardness, fracture/cleavage, streak color and any other characteristics in the table
below for each mineral. Some minerals may not have other characteristics, in that case put
“N/A” in the box.
Step 6
In table 2, provide two common uses for each mineral.
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For this lab, use the lab packet and any online resources to fill out table #1 with the correct
properties. In table #2, do some research and find out what each mineral is used for, list two uses
for each.
Notes: The luster of the mineral will either be metallic or nonmetallic. Some minerals don’t
always produce a streak when scratched across a streak plate.
**Number 1 is filled out as an example.
Plate Tectonics Lab (GLY 108)
Mineral Identification Chart, Lab 1
#
Color of
Mineral
Luster
of Mineral
Hardness
of Mineral
Fracture or
Directions
of Cleavage
Color of
Streak
Other
Characteristics
Name of
Mineral
1
Talc
Green to
White
Nonmetallic
1
Fracture
White
Smooth, soapy
feel
2
Gypsum
3
Calcite
4
Fluorite
5
Apatite
6
Feldspar
7
Quartz
8
Beryl (Topaz)
9
Corundum
10
Galena
11
Magnetite
12
Hematite
13
Halite
14
Sphalerite
8
15
Pyrite
16
Muscovite
17
Biotite
18
Olivine
Data Table 2
Common Mineral Uses
Mineral # & Name
Common Use: 1
Common Use: 2
#1 – Talc
#2 – Gypsum
#3 – Calcite
#4 – Fluorite
#5 – Apatite
#6 – Feldspar
#7 – Quartz
#8 – Beryl (Topaz)
#9 – Corundum
#10 – Galena
#11 – Magnetite
#12 – Hematite
#13 – Halite
#14 – Sphalerite
#15 – Pyrite
#16 – Muscovite
#17 – Biotite
#18 – Olivine
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