Background Information
The Mohs Hardness scale is based on hardest of ten common minerals. Diamonds are the hardest mineral, rating a 10, and talc is the softest mineral rating a 1. A scratch test is done to determine the hardest of the mineral.
Mohs Hardness |
Mineral |
1 |
|
2 |
|
3 |
|
4 |
|
5 |
|
6 |
|
7 |
|
8 |
Topaz (Emerald and Aquamarine) |
9 |
Corundum (Sapphire and Ruby) |
10 |
Diamond (Used in jewelry and cutting tools) |
On the Mohs scale:
Fingernail has a hardness of 2.5
Copper Penny has a hardness of 3.5
Knife Blade has a hardness of 5.5
Window glass has a hardness of 5.5
Sand paper has a hardness of 6.0
Emery board/Steel file has a hardness of 6.5