Question

sample 10:
luster:
this mineral does shine like a metal
hardness:
this mineral is scratched by a fingernail
breakage:
certain samples (like the second image to the left) break along smooth planes and flat surfaces
color:
observe the sample images to the left to determine color
streak:
observe the third image to the left to determine the color of the streak
other characteristics:
this mineral has a distinct greasy feel
29 multiple choice 3 points
what is the hardness of this mineral sample?
< 2.5
< 3
3 - 5.5

5.5

Explanation:

Step1: Recall Mohs hardness scale

Mohs hardness scale: fingernail is about 2.5.

Step2: Analyze mineral hardness

Mineral is scratched by fingernail (hardness 2.5), so its hardness is < 2.5.

Answer:

< 2.5