Mohs scale

n.
A scale for classifying minerals based on relative hardness, determined by the ability of harder minerals to scratch softer ones. The scale includes the following minerals, in order from softest to hardest: 1. talc; 2. gypsum; 3. calcite; 4. fluorite; 5. apatite; 6. orthoclase; 7. quartz; 8. topaz; 9. corundum; 10. diamond.

[After Friedrich Mohs (1773-1839), German mineralogist.]

A scale which rates the scratch hardness of a mineral on a scale of 1 (talc) to 10 (diamond).

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[Ge]

A general measure of hardness represented as a scale running between 1 (soft) and 10 (hard) in which each step is represented by a distinctive mineral: 1 = talc; 2 = gypsum; 3 = calcite; 4 = fluorspar; 5 = apatite; 6 = felspar; 7 = quartz; 8 = topaz; 9 = corundum; 10 = diamond. If a sample of material (e.g. pottery) can be scratched with one of these minerals then it is softer than that mineral; through a process of trial and error a sample's position on the scale can be determined.

The Mohs scale is a standard of 10 minerals by which the hardness of a mineral is rated. It was introduced in 1812 by the German mineralogist Friedrich Mohs (1773-1839). The minerals are arranged from softest to hardest. Harder minerals, with higher numbers, can scratch those with a lower number.

Hardness Mineral Comment

1 Talc Hardness 1-2 can be scratched by a fingernail

2 Gypsum Hardness 2-3 can be scratched by a copper coin

3 Calcite Hardness 3-6 can be scratched by a steel pocket knife

4 Fluorite

5 Apatite

6 Orthoclase Hardness 6-7 will not scratch glass

7 Quartz

8 Topaz Hardness 8-10 will scratch glass

9 Corundum

10 Diamond

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The noun has one meaning:

Meaning #1: a scale of hardness of solids; talc is 0 and diamond is 10; ordering is determined by which substance can scratch another substance

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