Mohs’ Hardness Scale

Friedrich Mohs introduced a popular hardness scale to quantify hardness, mainly to help in identification of minerals and gems.

Mohs’ Scale Rosiwal-grinding-hardness Material for comparison
Graphite
1 Talcium 0.03
Lead, tin
2 Gypsium, rock salt 1.25
Aluminium, zinc, magnesium, copper, silver, gold
3 Calcite 4.5 Marble, brass, iron, nickel
4 Fluorspar 5
Steels unhardened
5 Apatite 6.5
Window glass
6 Feldspar 37
Low-carbon steels, hardened
7 Quartz 120
0.9% C steel, hardened; tungsten
8 Topaz 175
Special Steels
9 Corundum 1000
10 Diamond 14000

Mohs' Equipment

There are pictures of Moh’s scientific instruments on the phase transformations group web page. Prof. Harry Bhadeshia photographed the equipment which is on display in Graz.

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7 Responses

  1. Its hard to make a comment on this.

  2. Heh, I wanted to compare other hardness scales but the table would become too complicated for this format.

    I learnt that Mohs’ name has an ‘S’ so it’s Mohs’ hardness rather than Mohs.

  3. A different hardness scale was used in a question on University Challenge last night. Diamond was 1.

  4. Sounds like it was a hard question.

  5. All the people that left comments below me are retarted,why would you leave a comment about a scale!

  6. I saw a paper about the meaning of hardness measurements by Tabor. (He also had a book). Reference is: D. Tabor, A physical meaning of indentation and scratch hardness, British Journal of Physics, Vol 7, p159, May 1956.

    Still no idea about hardness scale with diamond as “1”.

  7. i need to know where zinc is on this scale. can anyone help me?

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