MINERALS

Hardness

Click here to go back to the main page

Hardness is a measure of a mineral's resistant to abrasion. This property is easily determined and is used widely for field identification of minerals. More than a century ago. Friedrich Mohs (1773-1839), a German mineralogist, assigned arbitrary relative numbers to ten common minerals in order of their hardness.

Hardness	Mineral	Test
1	Talc	Fingernail (2.5)
2	Gypsum
3	Calcite	Cooper coin (3)
4	Flourite	Knife blade (5.5)
5	Apatite	Glass plate (5.5+)
6	K-feldspar
7	Quartz	Streak plate (7)
8	Topaz
9	Corundum
10	Diamond

Mineral Hardness Test Video

A simpler version of the Moh's scale can be established using three types of hardness:

SOFT - Minerals that can be scratched with a fingernail

INTERMEDIATE - Minerals that cannot be scratched with a fingernail but can be scratched with a steel nail.

HARD - Minerals that cannot be scratched with a steel nail.

Mineral	Hardness
Calcite
	INTERMEDIATE Mineral cannot be scratched with a fingernail but can be scratched with a steel nail.
Gypsum
	SOFT Mineral can be scratched with a fingernail
Pink Feldspar
	HARD Mineral cannot be scratched with a steel nail.
White Feldspar
	HARD Mineral cannot be scratched with a steel nail.
Gray Feldspar
	HARD Mineral cannot be scratched with a steel nail.
Quartz
	HARD Mineral cannot be scratched with a steel nail.

Click here to go back to the main page