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Minerals Study Guide



Modified True/False
Indicate whether the sentence or statement is true or false.  If false, change the identified word or phrase to make the sentence or statement true.
 

1. 

Although a few minerals are composed of single elements, most are made from compounds. _________________________

 

2. 

Minerals can form when differences in density force magma upward into warmer layers of Earth’s interior. _________________________

 

3. 

Mineral crystals may begin to precipitate out of a solution that has become saturated. _________________________

 

4. 

The most common minerals, feldspar and quartz, are carbonates. _________________________

 

5. 

Gems are prized for their great availability and beauty. _________________________

 

6. 

There are at least 3000 known minerals in Earth’s crust. _________________________

 

7. 

Minerals form from cooled magma and from elements in gases. _________________________

 

8. 

Minerals can be identified based on their physical and chemical properties. _________________________

 

9. 

The most reliable way to identify a mineral is by using a combination of several tests. _________________________

 

10. 

The classification of a mineral as an ore does not change once it has been mined. _________________________

 

11. 

Trace elements in a mineral do not affect the color or the value of mineral. _________________________

 

Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

12. 

Minerals always exist in a(n) ____ form.
a.
liquid
c.
solid
b.
gaseous
d.
organic
 

13. 

The most abundant elements in Earth’s crust are ____.
a.
aluminum and potassium
c.
oxides and carbonates
b.
halite and coal
d.
oxygen and silicon
 

14. 

Silver, gold, and copper have shiny surfaces and thus are said to have ____.
a.
dull luster
c.
waxy luster
b.
metallic luster
d.
nonmetallic luster
 

15. 

Ores near Earth’s surface generally are obtained from ____.
a.
waste-removal facilities
b.
underground mines
c.
open-pit mines
d.
bodies of water with high concentrations of dissolved minerals
 

Completion
Complete each sentence or statement.
 

16. 

A mineral, such as salt, is naturally occurring but ____________________, in contrast to sugar, which comes from plants.
 

 

17. 

A mineral can take the shape of one of the six major ____________________ systems.
 

 

18. 

____________________ make up the most common mineral group.
 

 

19. 

When compounds in cooling ____________________ no longer move freely, they may interact chemically to form minerals.
 

 

20. 

____________________ is described as either metallic or nonmetallic.
 

 

21. 

A mineral’s ____________________ rarely changes, but sometimes does not match its external color.
 

 

22. 

Mohs scale is used to compare the ____________________ of minerals.
 

 

23. 

Mica has perfect ____________________ in one direction; it breaks in sheets.
 

 

24. 

When flint and opals break, they have a unique ____________________ with arclike patterns.
 

 

25. 

Geologists commonly use _________________________ as a measure of density for accurate identification of a mineral.
 

 

Matching
 
 
Match each item with the correct statement below.
a.
cleavage
d.
luster
b.
fracture
e.
specific gravity
c.
hardness
f.
streak
 

26. 

Ratio of the weight of a substance to the weight of an equal volume of water
 

27. 

Property of splitting along one or more flat planes evenly and easily
 

28. 

Property of breaking with rough or jagged edges
 

29. 

Measure of how easily a mineral can be scratched
 

30. 

Color of a mineral when it is broken up and powdered
 

31. 

The way a mineral reflects light from its surface
 
 
Match each item with the correct statement below.
a.
crystal
d.
mineral
b.
gem
e.
ore
c.
magma
f.
silicate
 

32. 

Naturally occurring, inorganic solid with specific chemical composition and crystalline structure
 

33. 

Solid in which the atoms are arranged in repeating patterns
 

34. 

Molten material found beneath Earth’s crust
 

35. 

Mineral that contains silicon and oxygen
 

36. 

Mineral that contains a useful substance that can be mined for profit
 

37. 

Valuable mineral prized for its rarity and beauty
 

Short Answer
 

38. 

Discuss the unique characteristic of silica that is represented in the diagram below.

minerals_files/i0450000.jpg
 

39. 

Which is a more reliable method of identifying a mineral–streak or color? Explain.
 

40. 

How does the cost of removing waste material affect the classification of an ore?
 

41. 

Explain the meaning of the terms naturally occurring and inorganic as they relate to mineral characteristics.
 
 
Compare and contrast each pair of related terms or phrases.
 

42. 

cleavage, fracture
 

43. 

density, specific gravity
 

44. 

hardness, texture
 

45. 

luster, streak
 

46. 

What are three characteristics of a mineral?
 

47. 

If you took random samples of minerals from several locations, which type of mineral would you likely have more of—oxides, silicates, or carbonates. Why?
 

48. 

What accounts for the large diversity of silicates?
 

49. 

Why is color one of the least reliable tests for identifying minerals? Give an example to support your answer.
 

50. 

Why are some minerals classified as gems? Give three examples of gems.
 

51. 

A solution is nearly saturated with dissolved minerals. What will happen if 50 percent of the water in the solution evaporated?
 

52. 

What conditions typically result in the formation of large, well-shaped mineral crystals?
 

53. 

What can you conclude about the atomic bonds along a plane of cleavage?
 

54. 

Why do geologists usually use a combination of tests to identify a mineral?
 

55. 

What mineral would you use to polish a piece of corundum? Why?
 

56. 

Which mineral would react to iron filings—magnetite or graphite? What special property would that mineral have?
 

57. 

What three factors should be considered before mining a newly found mineral deposit?
 
 
Use this table for the six mineral samples to answer the following questions.

Mineral
Specific Gravity
Chemical Formula
Breakage Pattern
Gold
19.3
Au
Hackly
Apatite
5
Ca5(PO4)3(F, OH, Cl)
Uneven fracture
Pyrite
5.2
FeS2
Uneven fracture
Garnet
3.5–4.3
(Mg, Fe, Ca) 3 (Al2Si3O12)
Conchoidal fracture
Beryl
2.75
Be3Al2Si6O18
Uneven fracture
Corundum
4
Al2O3
Fracture
 

58. 

If the volume of the sample of pyrite equals the volume of the sample of gold, how many times greater is the mass of the gold sample than the mass of the pyrite sample?
 

59. 

How can the breakage pattern be used to distinguish between gold and pyrite?
 

60. 

Which of the six minerals is a native element?
 

61. 

List the six minerals in order from most dense to least dense.
 

Problem
 

62. 

Your task is to determine the relative hardness on the Mohs’ scale of two everyday objects—a penny and a steel pocketknife. You also have samples of gypsum, fluorite, and quartz. By experimentation, you determine the following: The penny scratches gypsum, but it doesn’t scratch quartz, fluorite, or the knife blade. The knife scratches gypsum, fluorite, and the penny, but it doesn’t scratch quartz. What is the hardness of the penny? What range of Mohs’ values can the knife blade have?

Mohs Harness Scale
 
Hardness
 
Hardness of
Common Objects
Talc
1 (softest)
  
Gypsum
2
 
fingernail (2.5)
Calcite
3
 
piece of copper (3.5)
Fluorite
4
 
iron nail (4.5)
Apatite
5
 
glass (5.5)
Feldspar
6
 
steel file (6.5)
Quartz
7
 
streak plate (7)
Topaz
8
 
scratches quartz
Corundum
9
 
scratches topaz
Diamond
10 (hardest)
 
scratches all common materials
 
 
Three pairs of mineral samples are brought to you for testing. Both samples in one pair look like gold, but one is pyrite, or fool’s gold. Both samples in the second pair look like emeralds, but one is nonprecious apatite. Both samples in the third pair look like rubies, but one is a less valuable garnet. Use the information in the table to complete the dichotomous key to identify each mineral.

Mineral
Color
Hardness
Gold
Metallic gold
2.5–3
Apatite
Blue, green
5
Pyrite
Metallic pale brass, gold
6–6.5
Garnet
Red, deep red, brown
6.5–7.5
Beryl
Bluish green, green
7.5–8
Corundum
Red, deep red
9
 

63. 

Which mineral can scratch at least one of the green stones?
 

64. 

Which mineral can scratch neither green stone?
 

65. 

Which mineral can scratch at least one of the red stones?
 

66. 

Which mineral can scratch neither red stone?
 

67. 

Which mineral can scratch only one of the green stones?
 

68. 

Which mineral can scratch both green stones?
 



 
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