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Unit 1 Lab Assignment Activity 1

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Unit 1 Lab Assignment

Activity 1.1: Mechanical Cohesion Properties of Minerals

Question 1:

Images (a) and (b) are two mineral samples, calcite and limonite respectively. Describe any cleavage or fracture exhibited in the samples and explain how you came to your conclusions regarding the samples.

Image a:

          

 

Image b:

  

Photos by L. Curtis – (a) Calcite (b) Limonite

 

A:

 

B:

 

Question 2:

Image (c) is a sample of dolomite. A student attempts to scratch the surface with his fingernail and is unable to do so. Then, he scratches the sample against a piece of glass, which remains unscratched. What assumptions can be made about the sample?

Image c:

 

Photo by L. Curtis – (c) Dolomite

 

C:

 

 

 

Activity 1.2: Optical Properties of Minerals

 

Question 3:

Determine the streak of the samples below.

 

 

Cinnabar:

 

Pyrite:

 

Question 4:

Calcite exhibits double refraction. Explain what that means.

 

 

Response:

 

Activity 1.3: Special Properties of Minerals

Question 5:

Below you will see images of Sulfur, Magnetite and Calcite. Using internet research, write an explanation for each sample about the special properties that could help a student to identify these minerals.

 

Sulfur:

 

 

 

 

 

Magnetite:

 

 

 

 

 

 

 

 

Calcite:

 

 

 

 

 

 

Activity 1.4: Identification of Minerals

Question 6:

Using the provided definitions and the identity tables below as a guide, identify the mineral samples given to you by your instructor in the Lab 1 Video.

 

Sample                 Hardness             Streak   Color     Cleavage/ Fracture          Specific Gravity                 Diaphaneity        Other

Properties           Name

1                                                                                                                             

2                                                                                                                             

3                                                                                                                             

4                                                                                                                             

5                                                                                                                             

6                                                                                                                             

7                                                                                                                             

8                                                                                                                             

9                                                                                                                             

10                                                                                                                          

 

 

Mineral Identification Tables

Metallic to Sub-Metallic Luster Minerals

Hardness             Streak   Color     Cleavage/ Fracture          Specific Gravity Other Properties              Name

1              green to blue/gray          gray       Cleavage - 1 dir.                4.7          greasy feel          Molybdenite

1 - 1.5    gray to black       gray to black       Cleavage - 1 dir.                2.25        greasy feel          Graphite

1.5 - 2    gray to black       indigo blue          Cleavage – 1 dir.               4.68        iridescent yellow and red             Covellite

2.5          Gray      gray       Cleavage – 3- dir.             7.5                          Galena

2.5 - 3    black to lead gray             black to lead gray             Fracture               6.46        brittle    Chalcocite

3              gray-black           bronze, iridescence that is red-purple    Fracture               5.0                          Bornite

3.5 – 4   green-black        brassy yellow, often tarnished   Fracture               4.2          most common copper mineral                Chalcopyrite

4 – 5.5   yellow-brown to red      yellow-brown, orange-brown, dark brown          Fracture               2.7-4.3                  Limonite (Goethite)

4.5 - 5    reddish-brown  steel-gray to red-brown               Fracture               4.5          most common iron mineral                Hematite

5.5 – 6.5               Black      black      Fracture               5.0          strongly magnetic            Magnetite

6 – 6.5   green to brownish black               gold to pale brassy yellow            Fracture               5.0                          Pyrite

 

Non-Metallic Luster Minerals

Hardness             Streak   Color     Cleavage/ Fracture          Specific Gravity Luster   Name

1              White    white    Cleavage – 1 dir.               2.8          pearly or greasy / dull    Talc

1 – 2.5   Yellow   yellow   Fracture                               pearly   Sulfur

2              White    colorless, white, gray, yellow      Fracture               2.1 – 2.4               vitreous               Gypsum

2.5          White    colorless, blue, yellow-blue         Cleavage – 3 dir.               2.2 – 2.4               vitreous               Halite

2.7 – 3.1               gray to white     black, dark green or brown          Cleavage – 1 dir.               2.8          vitreous or pearly                Biotite Mica

2.7 - 3    White    gray, green or colorless Cleavage – 1 dir.               3.0          vitreous               Muscovite Mica

3              White    colorless or white            Cleavage – 3 dir.               2.7          vitreous               Calcite

3 – 3.5   White    colorless or white            Cleavage – 2 dir.               4.5          vitreous               Barite

3 – 3.5   White    white, gray, brown, pink               Cleavage – rhombic                        vitreous or pearly            Dolomite

3.5 - 4    Green   Green   Fracture               4.0          silky to dull          Malachite

3.5 – 4   light yellow to brown     dark brown, black or yellow        Cleavage – 6 dir.               4.0          resinous to sub-metallic

adamantine        Sphalerite

4              White    colorless, white, yellow, purple, blue, green       Cleavage – 4 dir.               3.0          vitreous                Fluorite

5              White    yellow, green, blue, brown         Fracture                               vitreous               Apatite

6              Gray      dark green to black         Cleavage – 2 dir.                               vitreous               Augite (Pyroxene)

6              gray-white          dark green, black, or brown        Cleavage – 2 dir.               3.0          vitreous               Hornblende (Amphibole)

6              white or gray     olive green to brown      Fracture                               vitreous to adamantine Olivine

6              colorless to white            white to dark gray           Cleavage – 2 dir.               3.0          vitreous               Plagioclase Feldspar (Albite, Labradorite, etc.)

6              colorless to white            white, tan, red, orange, green, colorless               Cleavage – 2 dir.               2.5                vitreous or pearly            Potassium Feldspar (Orthoclase, Microcline)

7              colorless              colorless, white, gray, purple, pink, black, yellow, green                Fracture               2.6 – 3.5                vitreous               Quartz

9              colorless              gray, brown, blue, red, colorless               Fracture               4.0 – 4.5               dull to vitreous, adamantine        Corundum

8              colorless to white            clear, brown, black, tan Cleavage - Orthorhombic             3.5          vitreous               Topaz

 

 

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