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7.11: Lab Exercise (Part C) - Geosciences

7.11: Lab Exercise (Part C) - Geosciences


Overview

Take out Minerals Bag 3 and lay the six mineral samples out on a white sheet of paper. We will first examine several properties, including streak, from these six samples, and will answer more questions about them later in the lab. Look closely at each of the minerals, using the hand lens to observe them. In this bag, you have the following minerals (not listed in order): Magnetite, Graphite, Copper, Sulfur, Hematite, and Pyrite. They are numbered 13-18.

15. Sample 13: What is the streak of this sample?

a. dark gray streak

b. white streak

c. reddish brown streak

d. pale yellow streak

16. Sample 13: What is the luster of this sample?

a. non-metallic, vitreous

b. non-metallic, earthy

c. non-metallic, greasy

d. non-metallic, waxy e. metallic

17. Sample 14: What is the streak of this sample?

a. dark gray to black streak

b. reddish-brown streak

d. pale yellow streak

18. Sample 14: Which other item(s) is/are characteristic(s) of this sample?

a. stains the fingers

b. harder than glass

c. greasy feel

d. both a and b

e. both a and c

19. Sample 15: What is the streak of this sample?

a. pale yellow streak

20. Sample 16: What is the luster of this sample?

a. non-metallic, waxy

e. metallic

21. Sample 16: Due to its appearance, this sample has often been confused with native gold, a mineral with a hardness of 2.5-3. How does its hardness compare with that of gold?

a. Sample 16 is harder than gold.

b. Sample 16 is softer than gold.

22. Sample 17: What is the streak of this sample?

a. pale yellow streak

23. Sample 17: What another unique property does this sample have?

a. effervescence in acid

b. it is magnetic

c. it tastes salty

d. it feels soapy

e. it writes on paper

24. Sample 18. Examine this entire sample closely with a hand lens. What is the luster of this sample?

a. metallic

Now that you have had practice at detecting the properties of your 18 mineral samples, take the next step of identifying each sample and answering the questions below. Use the Mineral Identification Chart (Figure 7.22) to help you.

25. Sample 1: What is this sample?

a. Microcline

b. Fluorite

c. Quartz

d. Olivine

e. Talc

f. Selenite (Gypsum)

26. Sample 2: What is this sample?

a. Selenite (Gypsum)

Mineral Identification Chart

LusterHardnessCleavageOther PropertiesMineral Name
Non-Metallic> GlassPoor CleavageRed-brown, black, silver in color. H=6. St=red-brownHematite
Olive-green in color. St=white. Commonly granularOlivine
Variety of colors. H=7. Conchoidal fracture. Vitreous luster.Quartz
Clearly Shows CleavageBlack to greenish-black in color. C=2 planes at ~60° and 120°. Elongated crystals.Amphibole
Tan-pink, white, green in color. C=2 planes at 90°.Microcline
Black to greenish-black in color. C=2 planes at ~90°. Short stubby crystals.Pyroxene
< GlassPoor CleavageDark gray to black in color. H=1. Greasy feel - will smudge fingers.Graphite
Yellow in color. H=1.5-2.5. St=white to yellow.Sulfur
White to green in color. Soapy feel.Talc
Clearly Shows CleavageBrown to black in color. H=2.5. C=1 perfect. Breaks into thin sheets that are elastic.Biotite Mica
White to transparent in color. H=3. C=3 rhombohedral. Strong effervescence in acid.Calcite
Transparent, yellow, purple, green in color. H=4. C=4 - octahedral.Fluorite
Transparent to white in color. H=2. C=3, though 2 directions may be difficult to see.Gypsum
White to transparent in color. C=3, cubic. Tastes salty.Halite
Transparent, light brown, to yellow in color. Breaks into thin sheets that are elastic.Muscovite Mica
Metallic> GlassPoor CleavageBlack in color. St=black. Strongly magnetic.Magnetite
Brass-yellow in color. H=6.5. St=dark gray.Pyrite
< GlassPoor CleavageCopper-red in color. Tarnishes to green or black in air. H=2.5-3. St=copper-red.Copper

27. Sample 3: What is this sample?

a. Selenite (Gypsum)

28. Sample 4: What is this sample?

a. Selenite (Gypsum)

29. Sample 4: What other unique property does this sample have?

a. it is magnetic.

c. it tastes salty.

d. it feels soapy.

e. it writes on paper.

30. Sample 5: What is this sample?

a. Selenite (Gypsum)

31. Sample 6: What is this sample?

a. Selenite (Gypsum)

32. Sample 7: What is this sample?

a. Pyroxene

b. Muscovite Mica

c. Halite

d. Amphibole

e. Calcite

f. Biotite Mica

33. Sample 7: What other unique property does this sample have?

a. it writes on paper.

34. Sample 8: What is this sample?

a. Biotite Mica

35. Sample 8: What other unique property does this sample have?

a. it writes on paper.

36. Sample 9: What is this sample?

a. Biotite Mica

37. Sample 10: What is this sample?

a. Biotite Mica

38. Sample 10: Test this tenacity of this mineral by trying to bend it. Which way does it behave?

a. sectile

b. malleable

c. elastic

d. brittle

39. Sample 11: What is this sample?

a. Biotite Mica

40. Sample 12: What is this sample?

a. Biotite Mica

41. Sample 13: What is this sample?

a. Magnetite

b. Graphite

c. Copper

d. Sulfur

e. Hematite

f. Pyrite

42. Sample 14: What is this sample?

a. Pyrite

43. Sample 15: What is this sample?

a. Pyrite

44. Sample 16: What is this sample?

a. Pyrite

45. Sample 17: What is this sample?

a. Pyrite

46. Sample 18: What is this sample?

a. Pyrite

Mineral Notation Chart

Fill in this chart as you work through the lab. An example of a mineral you do not have in your kit (#0) is included. You do not have to fill out every column for every mineral – just follow along in the lab and determine the properties you are asked about.

Mineral # LusterHardness Cleavage/Fracture Streak Other Notable Properties (include color when diagnostic) Name
0Metallic~2.5 – May scratch fingernail3 - cubicGrayHigh specific gravity because it is heavyGalena

Watch the video: Rock Physics u0026 Geomechanics Laboratory - School of Geosciences