ESSE1012_lab2_2024
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LE/ESSE 1012 3.0
The Earth Environment
Winter 2024
Lab. Section: Name: Student Number: LAB 2: MINERALS
Due February 2, 2024, 10PM ET
IMPORTANT: This is a hands-on lab. You must attend the lab session in person in order to
receive credit for this lab.
Unless otherwise indicated, show your work for all problems. You can either enter your
answers into this document electronically using a computer or tablet, or you can print this
document, handwrite your answers in the spaces provided, and scan the pages. If you need
additional space, you can insert additional pages or you can add additional space within the
Word document. For all numerical answers, the units should be indicated. Students can
discuss this lab with each other, but copying from each other or copying from other sources is
cheating and is not permitted. You should not share your answer sheets with other students or
look at the answer sheets of other students. You should understand the concepts well enough
to explain your answers in your own words. Your answers for hands-on portions of the lab
should be based on work that you yourself performed in the lab location. If the lab procedure
indicates that you can form groups to complete particular tasks, then you should still be
physically present in the lab location contributing to the completion of those tasks, and you
should write the names of other group members on your answer sheets. If your work relies on
information that is obtained from a legitimate source other than ESSE 1012 course materials,
please indicate the source of that information with enough detail so that someone else can
locate the source. Please see the course outline for detailed policies.
Although there are thousands of known minerals, over 99% of the rocks on Earth are made up of
fewer than 20 minerals. In this laboratory exercise, you will examine the properties of these 'rock
forming' minerals.
The goal of this lab is to have you use the physical properties of crystalline solids to identify
common rock forming minerals. In the process, you will use Tables A.1 and Table A.2 from the
Jarvis text (available on eClass), along with the concepts covered in the lecture and Chapter 7 of the
McConnell text
.
LE/ESSE 1012 Lab 2 - Winter 2024 ©NTandon
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1.
COLOUR, STREAK AND LUSTRE
You are provided with the following samples:
Mineral Name
Lustre
Pyrite
Metallic Quartz
Vitreous (glassy)
Kaolinite
Dull Earthy
Talc
Pearly
Examine each sample and be sure that you can recognize each type of lustre before moving
on.
Use the streak plates (made of unglazed porcelain) along with your recently acquired
knowledge of lustre to determine the colour, streak and lustre of the given minerals below.
Non-Silicates:
magnetite
oolitic hematite
limonite
sphalerite
galena
pyrite
Silicates:
kaolinite
amphibole
garnet
a)
Complete the following table from your results (3 marks for each mineral)
Mineral
Colour
Streak
Lustre
Magnetite (#71). Black. Black. SubMetallic Oolitic hematite (#75). Maroon Reddish brown Dull earthy Limonite (#73). Orange brown. Yellowish brown. Earthy
Sphalerite (#66). Brownish black Light brown. adamantine.
Galena (#77). Silver. Dark grey. Metallic Pyrite (#78). Brass yellow. Grey Metallic Kaolinite (#82). White. White. Dull earthy Amphibole (#62). Dark green. None. Sub metallic
LE/ESSE 1012 Lab 2 - Winter 2024 ©NTandon
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Garnet (#67). Brownish black None. Waxy
b)
Was streak colour useful for all of the minerals? Why or why not? If not, indicate the
lustre(s) of the mineral(s) for which streak was not useful. Was there a particular group
that streak was useful for? (4 marks)
Streak color was a useful property for identifying most minerals. It's especially handy for
metallic minerals like magnetite, galena, and pyrite, as well as minerals with a vitreous luster
such as garnet and amphibole. However, for minerals like sphalerite with an adamantine
luster the streak color wasn’t as useful for identification.
c)
Suppose that you encounter a rock sample with earthy lustre, and you wish to determine
its mineral composition. One portion of the rock sample produces a reddish brown streak
and another portion of the rock sample produces a yellowish brown streak. How would
you interpret these results? (4 Marks)
The rock sample has two unique streak colours. Means there’s two different minerals in the
stone. The reddish-brown streak is most likely caused by oolitic hematite, whereas the yellowish-
brown streak indicates that limonite may also be present in the sample.
d)
Pyrite is commonly known as “fool’s gold” because it has some physical properties
similar to gold. Give two
different physical properties that you would use to identify
pyrite as distinct from gold? (4 Marks)
Two different properties could be streak colour and pattern difference.
1.Pyrites leaves a grey or brownish black streak while the gold leaves a golden yellow streak.
2. Pyrites looks more sharp edges and faces while gold is more grains without well defined
crystal faces
2. HARDNESS
You have been provided with 5 of the 10 minerals in the Mohs’ hardness scale. In increasing
order of hardness you will find: 1 – Talc 7 – Quartz
3 – Calcite
9 – Corundum
4 – Fluorite
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a)
Using the above minerals, determine the hardness bounds of a copper coin. Explain your
approach. (4 marks)
We Begin with the softest (talc) and proceeding to the toughest (corundum). we checked which
minerals scratch the coin. The coin wasn’t damaged by corundum so the hardness is more than 7.
By doing that we can tell The hardness bounds of the copper coin fall between the hardness of
fluorite (4) and quartz (7).
b)
The hardness of glass changes with its chemical composition. Determine the approximate
hardness of the glass plate provided in the lab. (4 Marks)
The glass plate was only scrateched by minerals with hardness 4, 7 and 9. c)
If you had a sample of what you believe is fluorite, how would you identify it? (4 Marks)
Fluorite looks more cubic crystal. We can also identify with colours and transparency. Since it
include purple, green, blue and clear. 3.
CLEAVAGE
Examine your mineral specimens to observe the physical property known as cleavage. a)
Why is cleavage an important physical property? (4 Marks)
Cleavage helps us determine the type of mineral we're working with by seeing how it breaks up.
This breaking pattern reveals a lot about the crystal structure of the mineral. In addition, it can
provide information on the mineral's quality. For example, some minerals break very smoothly
and uniformly, and others aren’t. So, it’s an important physical property to determine materials
behaviour and usage.
b)
How does cleavage originate in minerals? (4 Marks)
Cleavage can originate when the earth tectonic plates collide. As a result, the rocks get shifted.
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the pressure from squeezing and shifting changes rocks development such as, it can create
certain lines around or make it weaker. And overtime that weak spot becomes cleavage in
minerals.
c)
Explain in your own words why mica does not
have three
directions of cleavage (a
diagram might help with your explanation). (4 Marks)
Mica doesn’t have three
directions of cleavage since its atomic arrangements doesn’t allow it.
Mica can only have one directional cleavage due to its symmetry. The lack of symmetry limits
the ability to to have three
directions of cleavage.
d)
Suppose a mineral has three
directions of cleavage (e.g., calcite). How many faces will a
crystal of the mineral have? Why? (4 Marks)
If the mineral has three directions of cleavage, the crystal of mineral will have six faces.
For example, cutting a cube into six smaller Piece. Each piece will have a flat face like
parallelogram. The cleavage planes come together at specific angles and creates six
smooth faces on the crystal.
4.
MINERAL IDENTIFICATION
You are provided with ten unknown minerals. Using concepts covered in the lecture notes
and other course materials, identify all of these minerals. Complete the following table. For
each mineral, list
only
the diagnostic properties (not
every property) that you used to identify
it. Use the following format (3 marks for each mineral):
Mineral #
Mineral Name
Main Diagnostic Properties
U1 Hornblende Black, no lustre, stretches coppers. U2. Garnet. Dark reddish, scratches glasses, cleavage lines.
U3 Felspar Dark reddish, stretches glasses, perfect clavage
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U4 Calcite. Colourless, glossy & no streak U6 Pyrite. Golden yellow, scratches glass & black streak
U8 Biotite ( mica ) Black, grey streak & 1 cleavage line.
U9 Muscovite Silver, scratches glasses
U10 Magnetite Brownish black, grey streak & no cleavage. 5.
EXAMINATION OF AN IGNEOUS ROCK
Examine the igneous rock sample provided in the lab and answer the following questions.
a)
Are there any visible features that make clear that the rock you are examining is an
igneous rock rather than a metamorphic rock? If so what are they? (3 Marks)
We can easily tell by examining rocks texture if it’s igneous or metamorphic. Igneous
rock usually looks shiny, glossy and often has mineral crystalline. Metamorphic rock is
usually foliated, non foliated and squished.
b)
Identify two felsic
minerals in the sample. What features did you notice in order to
identify these minerals? (3 Marks)
Two felsic materials in the sample are calcite and quartz.
Calcite is often white or colourless. Quartz comes with different colours such as grey, black,
purple & brown. Calcite has a perfect rhombohedral cleavage meanwhile quartz typically
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lacks cleavage. c)
Identify one mafic
mineral in the sample. What feature(s) did you notice in order to
identify this mineral? (3 Marks)
One mafic mineral is Magnetite. We can identify magnetite with its rich brown-black hue and
gray stripe and absence of cleavage lines. Magnetite was one of the minerals that best exhibited
the distinctive qualities of mafic minerals.
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