Correct Answer - Option 3 : hardness
Concept:
Moh's Hardness scale:
Friedrich Mohrs, a German mineralogist, developed the scale in 1812. He selected ten minerals of distinctly different hardness that ranged from a very soft mineral (talc) to a very hard mineral (diamond).
In general, Mohs invented a scale of hardness based on how one mineral scratched another. The Moh's scale is not a linear scale. Instead, it ranks gems on a relative scale based on their scratch hardness.
Hardness Numbers for different minerals based on Moh's scale are:
|
Mineral
|
Scale Number
|
|
Talc
|
1
|
|
Gypsum
|
2
|
|
Calcite
|
3
|
|
Fluorite
|
4
|
|
Apatite
|
5
|
|
Feldspar
|
6
|
|
Quartz
|
7
|
|
Topaz
|
8
|
|
Corundum
|
9
|
|
Diamond
|
10
|
