AnswersEarth and Space ScienceProperties of Minerals

Properties of Minerals — Quiz Answers

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1
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Which property most clearly distinguishes sample C from all the other samples?

A
white streak
B
cleavage in two directions
C
nonmetallic luster
D
conchoidal fracture
3

At a gemology research center, two clear, colorless minerals were brought in for testing. Both formed six-sided crystals and looked nearly identical, which initially suggested they might share the same properties. Scratch testing revealed a sharp contrast: one fractured easily under a knife blade, while the other resisted scratching even from a steel file. This unexpected difference led the team to consider how internal bonding might explain the variation in hardness despite their similar outward appearance. Which conclusion best explains the difference in hardness between the two minerals?

A
Because both minerals form six-sided crystals, they should belong to the same classification group regardless of hardness.
B
Minerals with similar external features usually have the same hardness, so these results are inconsistent with expectations.
C
The mineral that fractured easily likely has weaker bonds between layers, while the resistant one has stronger bonding throughout.
D
Differences in hardness are mainly controlled by visible traits such as clarity and luster rather than atomic bonding.
4

During a mapping project in the Colorado Plateau, a geologist described a mineral from a sandstone outcrop as metallic and hard, based on its shiny luster and dark surface color. Laboratory analysis showed the sample was soft, nonmetallic, and left a pale streak on porcelain. The research team revisited the original field notes to evaluate what observational reasoning had led to the misclassification. What explanation best accounts for the error in the geologist’s field interpretation?

A
Weathering and light conditions can create a metallic appearance that misrepresents a mineral’s true nature.
B
The description assumed surface appearance reflected internal structure, which is not always the case.
C
The mineral’s reflective surface and dark color do not reliably indicate hardness or metallic content.
D
The field notes overemphasized chemical traits instead of confirming properties with simple visual tests.
5

During a mapping exercise, a geology student examined a sedimentary outcrop and recorded the following in their notes: “The well-rounded grains must be mica, since minerals with perfect cleavage are the most durable during transport. The fine clay beds here likely formed when quartz broke down under burial conditions.” When reviewing the notes, the supervising geologist questioned the accuracy of this interpretation. Which correction most accurately addresses the flawed logic in the student’s interpretation?

A
Minerals with perfect cleavage always remain intact, and quartz always turns into clay when buried.
B
The student’s explanation is entirely correct, and no further evidence is required to support it.
C
Mica’s cleavage makes it resistant to abrasion, so it often persists as rounded grains far from its source.
D
Quartz does not commonly break down into clay, and cleavage is not a reliable indicator of transport durability.
6

During a mapping exercise, a geology student examined a sedimentary outcrop and recorded the following in their notes: “The well-rounded grains must be mica, since minerals with perfect cleavage are the most durable during transport. The fine clay beds here likely formed when quartz broke down under burial conditions.” When reviewing the notes, the supervising geologist questioned the accuracy of this interpretation. Which correction most accurately addresses the flawed logic in the student’s interpretation?

A
Quartz does not commonly break down into clay, and cleavage is not a reliable indicator of transport durability.
B
Mica’s cleavage makes it resistant to abrasion, so it often persists as rounded grains far from its source.
C
Minerals with perfect cleavage always remain intact, and quartz always turns into clay when buried.
D
The student’s explanation is entirely correct, and no further evidence is required to support it.
7

Match each geologic setting or process to the mineral property that results from it.

Answer:

mineral reacts and fizzes|mineral cleaves into flat sheets|mineral forms fine, glassy texture|mineral dissolves easily

8

What inference can be drawn about the relationship between atomic symmetry and external crystal shape in the modeled halite variations?

A
Atomic symmetry is unrelated to any observable mineral properties.
B
Lower atomic symmetry produces irregular external crystal forms.
C
Crystal shape is unaffected by internal atomic symmetry.
D
Higher atomic symmetry produces irregular external crystal forms.

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