Environmental Geology 103L

Names

__________________ _____________________________________ _____________________________________ _____________________________________

Minerals and Earth Resources PART I. NEWS ALERT! 1. BACKGROUND INFORMATION, which you need to know to complete this lab: 

Man found dead in the restroom at the Jesse James truck stop in the Ampersand Mountains.



Coroner has declared his death a murder, of which 5 locals are being held as suspects.



The victim was identified as Rufus, a known scam artist who has been conning numerous individuals in the area.



Rufus’s clothes are covered with dust and there are mineral particles in his pockets, on his shoes and in his car. As such, the local police have hired an elite team of forensic geologists to aid in the solving of this case. The police have mineral particles found on the body as well as on each of the suspects.



Police have requested your team’s forensic specialists help in solving this murder. They need your team’s expertise in identifying the minerals and determining where these specimens came from. This identification can be done based on either the particular type of mineral OR based on how these minerals are used.

1. What are some physical properties of minerals that would help us identify the minerals found on the victim?

2.

How would knowing the everyday uses of minerals help us to solve this case?

PART II. HOW DO YOU IDENTIFY MINERALS? Important Information for Part II:     

You will now explore some common minerals and become familiar with the basic properties that will allow you to identify them. These distinguishing features will come in handy when you are trying to ID the specimens on the victim and the suspects. Note that when trying to identify an unknown mineral, a series of key questions can be asked so that each answer eliminates a group on minerals until only a few remain (See Figure 3.7. pg 69). Refer to Chapter 3, page 56-80 in your lab manual exercise for information on identifying minerals. BE SURE to only use the mineral specimens listed next to each property to explore that property.

1

A. MINERAL HARDNESS Mineral Specimens: 3, 7, 25, 33 Read Section 3.4.5 on page 62, in your lab manual and refer to Table 3.1 and Figure 3.3 for help with this activity. 1. Select minerals 3 and 33. a. Which mineral is harder? b. How do you know this? 2. Use the scratch test to determine the relative hardness of the minerals 3, 7, 25, and 33. 3. Rank them from softest to hardest and arrange them in a line of increasing hardness. HINT: Look for the powder or scratch left behind – the one that creates the powder/scratch is the harder mineral because it MADE the scratch so it has to be the harder. 4. List them by their specimen number: (softest) _____, _____, _____, _____ (hardest) Several “tools” that are not minerals may also be used to test hardness. However, you must first know the hardness of the tool. For this test, you will use the following tools: your fingernail, a glass plate, a porcelain streak plate, a steel nail, and a copper penny.

Mohs Hardness Scale

Mineral Name

ID Number

Tool Hardness

(your specimen)

(based on Mohs Scale)

1

Talc

______

2

Gypsum

______

3

Calcite

4

4

Fluorite

8

5

Apatite

no specimen

6

Feldspar

15

7

Quartz

______

8

Topaz

no specimen

9

Corundum

______

10

Diamond

2.5 Fingernail 3.5 Copper Penny 4.5 Steel Nail 5.5 Glass Plate 6.5 Streak Plate

no specimen

5. Using the scratch test on the minerals, determine the hardness of each tool and where it “fits” in relation to the hardness of the mineral specimens. Enter the mineral number in the correct order in the space provided. 6. On the list above, draw a line to separate the “hard” and “soft” minerals. 7. What tool will be most useful to initially determine if an unknown mineral is “hard” or “soft”? 8. What is the hardness of this tool?

2

Mineral Specimens: 1, 2, 28

B. LUSTER

Read Section 3.4.2 on page 60 in your lab manual for help with Luster. Go to the Appendix 3.1 on page 72-74 in your lab manual. Note that there one of the first is a heading that relates to LUSTER (metallic and nonmetallic). Luster is a description of how the surface of a substance reflects light. When confronted with an unknown mineral, you must first determine if the mineral is metallic or nonmetallic. Once you’ve determined this, then you will be able to proceed with the mineral identification, using the flowchart and numerous other mineral properties. 9. Determine the luster of the following specimens. The two main categories of luster are metallic or nonmetallic. Some nonmetallic lusters include: earthy, vitreous (glassy), greasy, and satiny. You only need to determine whether the mineral luster is METALLIC or NONMETALLIC. Specimen #

Luster (metallic OR non-metallic OR Both)

Mineral Name

1

Pyrite

2

Galena

28

Graphite

10. Look at specimens 11 and 12. One has a metallic luster; the other has an earthy nonmetallic luster. These specimens are actually the same mineral – hematite --, but have grown in different forms and, as a result, reflect light differently.

Mineral Specimens: 24, 36

C. MINERAL COLOR

Mineral color (Section 3.4.3, page 60, Figure 3.1) is the most noticeable property of a mineral specimen. For example fluorite may be purple, light blue, green or yellow. Some minerals occur in shades of only one color so that color can be used as a clue to their identity (i.e., color is diagnostic). Examine the mineral specimens 24, 36. These minerals always display the same color; hence color is a diagnostic tool we can use to identify them. 11. Using Appendices 3.1 and 3.2 on pages 72-80 in your lab manual, look up each of the minerals listed below and identify the specimens by their color and clarity.

Mineral Name

Color

Specimen #

sulfur

_________________

_______

copper

_________________

_______

3

Mineral Specimens: 11, 12, 28

D. STREAK

Streak (Section 3.4.4, page 60) is the color of a substance after it has been ground to a fine powder. A piece of unglazed porcelain, called a streak plate, is often used to test the streak of a mineral. Streak is frequently referred to as a mineral’s true color because the streak of one kind of mineral is usually the same regardless of color variety or clarity. 12. Using Appendices 3.1 and 3.2 on pages 72-80, look up each of the minerals listed below and identify the specimens by their streak. Note that for metallic minerals (those that reflect light like a metal), streak is the step that follows the hardness test. Specimen #

Mineral Name

Mineral Color

Streak Color

11

_________________

_________________

_________________

12

_________________

_________________

_________________

28

_________________

_________________

_________________

13. Find and name the mineral that has two forms, based on the similarity of their streaks. ____________

Mineral Specimens: 1, 7, 17

E. CRYSTAL FORM

14. Review Section 3.4.6 on Crystal Habit on page 63-64 (Figure 3.4) in the lab manual. Match the mineral specimen that displays each of the crystal forms listed below.

Crystal Form Prismatic

Specimen # ________

Mineral Name Quartz

Cubes

________

Pyrite

12-sides

________

Garnet

F. BREAKAGE: CLEAVAGE & FRACTURE

Mineral Specimens: 4, 6, 7, 15, 27

Breakage (Section 3.4.7, pages 64-66) discusses how minerals bonds either break along smooth planes or irregular fractures. The type of breakage can be a diagnostic tool for identifying minerals. Cleavage is the plane (surface) along which a mineral breaks when it is stressed. These planes are determined by the atomic structure of the mineral and the arrangement of atoms, just as is the shape of the crystal. Some minerals have several cleavage planes, with each plane oriented differently. Many minerals also have irregular surfaces when they break. These curved or irregular surfaces are called fractures. Use the following information below to identify the mineral specimens using the chart on the following page. Go to Figure 3.6 (pg 66) in your lab manual and closely examine the minerals and diagrams. 

Potassium feldspar also has two obvious directions of cleavage (2 @ 90o).



Halite has three cleavage surfaces that are oriented in a cubic arrangement (3 @ 90 ).

o

4



Calcite has rhombohedral cleavage and looks like a box that has been stepped on! (3 not at 90 )



Muscovite mica has one cleavage surface that allows the mineral to cleave in paper-thin sheets, referred to as cleavage in one direction.



Quartz does not break along a flat plane (i.e., it has no cleavage), but instead fractures in a curved, smooth form referred to as conchoidal fracture. Obsidian (a black, glass-like volcanic rock of the same composition as quartz) also displays conchoidal fracture. (fracture)

o

15. Use the following terms to describe the type of cleavage: one direction

2 @ 90

o

o

2 not at @ 90

o

3 @ 90

3 not at 90

o

fracture (no cleavage)

Mineral Name

Specimen #

Cleavage or Fracture Characteristics

potassium feldspar

______

__________________________________

halite

______

__________________________________

calcite

______

__________________________________

muscovite mica

______

__________________________________

quartz

______

__________________________________

G. DISTINCTIVE PROPERTIES

Mineral specimens: 4, 6, 13, 31

In addition to all of the other mineral properties investigated during this laboratory session (luster, hardness, cleavage, crystal form, etc.), some minerals have distinctive properties that few other minerals possess. Several of these distinctive properties are discussed in Sections 3.4.9-3.4.14, page 68 of your lab manual. Use the properties provided below and Appendices 3.1 and 3.2 on pages 72-80 in your lab manual to identify the minerals listed below. NOTE: The process of elimination is a valid tool. Mineral Name Magnetite

Distinctive Property is magnetic

Specimen # ______

Halite

tastes salty

______

Calcite

effervesces when dilute acid (HCl) is applied

______

Kaolinite

sticks to your tongue (swells when wet), smooth and soft

______

5

PART III. WHY DO WE CARE ABOUT MINERALS: EARTH RESOURCES Why is so important for our society and each of us to have an understanding of the minerals we just examined? Why are they so important? HINT: clues for uses as well as the identity of the mineral can be found in APPENDIX 3.1. 3.2 AND 3.3, pages 72-80 through the chemical formulas or the distinguishing properties.

A. ORE MINERALS Mineral Specimens: 1, 2, 11/12, Deposits of minerals from which valuable metals can be profitably recovered are called ores. The minerals in this section are but a fraction of the ores mined worldwide. Mineral 16. Bridges, cars, and other steel materials are made from these iron-rich minerals.

13, 36

Specimen #

___________________ _______ & ___________________

_______

___________________

_______

___________________

_______

17. Bullets, ammunition, and lead-based paints are made from this heavy, cubic mineral. ___________________

_______

18. Wiring and old coins are made from this shiny, soft mineral. ___________________

B. ECONOMIC MINERALS Mineral Specimens: Other non-metal minerals also widely utilized in our every day lives.

_______

3, 4, 24, 27, 28

Mineral 19. Babies and adults both enjoy using this extremely soft mineral in powdered form. ___________________

Specimen # _______

20. Glitter, make-up, and windows during Medieval times were made using this versatile mineral because of its ability to break easily into sheets

___________________

_______

21. Tums and Rolaids are made from this mineral because of its ability to neutralize acids. ___________________

_______

22. Not only is this greasy soft mineral found in pencils, but it is also widely used as an industrial lubricant.

___________________

_______

23. Even though this yellow mineral stinks, it is extremely valuable for use in drugs, explosives, fertilizers and insecticides because of its chemical composition. __________________

_______

6

C. EVAPORITES AND CLAYS Mineral Specimens: 6, 15, 25, 31 Evaporites are precipitated from evaporating mineral-rich waters in arid regions. As evaporation proceeds, the waters become more concentrated and minerals begin to crystallize and precipitate. The weathering of volcanic rock will produce feldspars and clays, both of which are very vital minerals in our societies. Mineral Specimen # 24. Which evaporite mineral has cubic cleavage and is used for de-icing roads, seasoning or preserving foods, water softeners?

_________________

_______

25. Which soft evaporite mineral can be scratched by your fingernail and is found in many buildings as drywall? It is also excellent for making sculptures.

_________________

_______

26. False teeth, ceramics and scouring powders are made from this hard pink mineral, with cleavage in 2 directions.

___________________

_______

27. The pure white clays of this very soft mineral are used for making fine china and pottery. ___________________

_______

D. SEMI/PRECIOUS MINERALS Mineral Specimens: 7, 11, 17, 33 Gemstones are defined by their color, luster, transparency, brilliance, durability, and rarity. Examples of some these stones are ruby, sapphire, emerald, and diamond. Less valuable, ‘semiprecious’ stones usually occur with small impurities and imperfections, but are still popular nonetheless. Mineral Specimen # 28. This 12-sided semi-precious gemstone is also valued for its abrasive properties because it is so hard. ___________________ _______ 29. Slight imperfections turn this mineral’s crystal form a very desirable shade of purple. ___________________ _______ 30. This iron-oxide mineral is popular today in necklaces, bracelets and earrings. ___________________

_______

31. Sapphires and ruby are gem-quality varieties of this extremely hard and very rare mineral. ___________________ _______

7

PART IV.MINERAL IDENTIFICATION EVERY STUDENT IS RESPONSIBLE FOR IDENTIFYING ALL MINERALS AND ALL USES.  List the KEY mineral properties used to identify the mineral (i.e. streak, luster, etc.)  You do NOT need to list every property for each mineral – only the ones YOU used to identify the mineral. Sample Number

Mineral Name

KEY Identifying Characteristics/Properties

Mineral Uses (from Part 3: Earth Resources)

1 2 3 4 6 7 11/12 13 15 17 24 25 27 28 31 33 36

8

PART V. FORENSIC GEOLOGY: THE CASE OF THE MURDER OF RUFUS THE SCAM ARTIST Scenario: Rufus is a scam artist who has been making enemies in the Ampersand Mountain area. Recently he was found dead in a women’s restroom at the local truck stop. The restroom had been cleaned recently, so any of the material found in the room is either from Rufus himself or his murderer. The problem is that while he was a pretty slick scam artist, he was not the cleanest of dudes and his clothes are covered in dust and there are particles on his shoes. Based on observations from local witnesses, the police have identified and are investigating 5 potential suspects. The police also have mineral particles from each of the suspects. INSTRUCTIONS: The police have asked your team of forensic geologists for help indentifying the minerals and determining how they arrived on the victim or in the restroom. 

Your team will determine this based on either the type of mineral OR the function of how these minerals are used.



Your team has a list of minerals and how they are used from previous research (Parts I –III of this lab).



You will use these resources to help you determine likely identity and probably origins and uses of the minerals.



You may refer to samples from your lab activities for comparison purpose, taking great care not to contaminate the police samples.



Keep notes on what you identified, how you did so, and any information given to you, using the chart on the last page of the lab.

The victim was found on the floor of the women’s restroom floor at the local truck stop. The following minerals were found on the body. The pathologist's report recorded that the death had been caused by a blow to the back of the head fracturing the skull. **Note: the minerals may appear more than once.

Victim: There was a wound on the victim’s head, which contained bits of Mineral A and Mineral B. On his right hand, police found Mineral C. On the victim’s clothing, left-side, police found Mineral D. At this time, there are 5 suspects with clear motives. Descriptions of those motives and what was found on each of the suspects are below.

Suspect 1: Female (Verna Mae) claims to have been in the woods near Ampersand Lake, now completely dry, camping alone at the time of the murder. Rufus was said to be having an affair with Verna Mae. Verna Mae works at the local Morton’s Seasoning Factory and said that she ended the affair and needed to get to nature for some emotional healing.

9

Question: Verna Mae is not necessarily the hiking type. She is very feminine and prissy, and was even wearing make-up (blue eye-shadow specifically), after the “hike.” Hmmm… Samples collected from: Hiking boots/Campsite > Mineral E and Mineral F Clothing/Face > Mineral G Under Fingernails > Mineral H Suspect 2: Male (Billy Bob) claims to have been four-wheeling around Ampersand Mountains and Ampersand Lake. Billy Bob was an old friend of Rufus but recently say they had a falling out over Verna Mae, Billy Bob’s sister. Billy Bob is the bartender of Billy’s Haufbrau, where he works evenings, and is the plant manager at the Antacid Factory, where he works the day shift. Billy Bob was overheard yelling at Rufus that if he messed around with or hurt Verna Mae anymore, he would not see the light of day. Samples collected from: Boots > Mineral J and Mineral K Four-wheel tires > Mineral L and Mineral M Under Fingernails > Mineral N Suspect 3: Male (Albus) claims to have been working in his garden retreat at the time of the murder. Albus was able to show police evidence of recently worked ground, indicating he was gardening at the time of the murder. Albus is a painter in the town, as well as an all around eclectic individual. He is known for his spiritual healing beliefs and he is often found scouring the mountains for samples from which to make jewelry and gifts. Rufus was known to have spread numerous rumors about Albus being crazy, which ruined Albus’s local business. Certain folks around town heard Albus chanting incantations, with the intent of casting a harmful spell over Rufus. Samples collected from: Under Fingernails > Mineral O Pockets > Mineral P Clothing > Mineral Q Suspect 4: Male (Cletus) claims to have been working late at his business, C.B.’s Construction and Electrician Services. Cletus is the owner and operator. He is a well-respected individual in town, but is also known for his angry outbursts. Cletus is running for city council. He is married (and has been for 6 years now) to suspect 5, Peaches, and they have 6 children. The police are not certain whether Cletus knew about the affair. Samples collected from: Pockets > Mineral R Clothing > Mineral S Soles of Shoes > Mineral T

10

Suspect 5 Female (Peaches, wife of Cletus) claims to have been in her pottery studio (located in the garage of her home) creating sculptures at the time of the murder. Peaches is the local artist who creates and paints local wildlife sculptures and other yard art, such as gnomes, flamingos, etc. Peaches was known to been having a heated affair with Rufus. The police have heard that Peaches was being blackmailed by Rufus so that her husband would not find out; however this is clearly hear-say. Samples collected from: Under Fingernails > traces of Mineral U and Mineral V Clothing/Face > Mineral W Soles of Shoes > Mineral X

32. Who is the murderer?

33. What led you to this conclusion? 34. Hypothesize how the murder “went down.” Explain the connection between the minerals found on the victim and those on the suspected murderer – how did the mineral from the murderer get on the victim and why was it on the suspect?

11

INDIVIDUAL

MINERAL ID

Victim

A

MINERAL NAME

NOTES

B C D Suspect 1

E F G H

Suspect 2

J K L M N

Suspect 3

O P Q

Suspect 4

R S T

Suspect 5

U V W X

12