Laboratory Manual for Introductory Geology 4e

FIGURE 3.2 Color and streak.
(a) Red hematite has a reddish brown streak.
(b) But this dark, metallic-looking specular hematite
also has a reddish brown streak.
EXERCISE 3.3
People Have Diagnostic Properties Too
Name:
Course:
Section:
Date:
Your father has asked you to pick up his old college roommate at the airport. You’ve never met him, but your father gave
you a yearbook photo and described what he looked like 30 years ago: height, weight, hair color, beard, eye color. Which of
these features would still be diagnostic today? Which, considering the passage of time, might be ambiguous? What other
properties might also be diagnostic? Indicate in the following chart which properties, considering the passage of time,
might be diagnostic and which might be ambiguous. Then suggest two others that would be diagnostic despite the years
that have passed.
Property Diagnostic (explain) Ambiguous (explain)
Height
Weight
Hair color
Beard
Eye color
Others
3.4 PHYSICAL PROPERTIES OF MINERALS
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