Mohs Scale

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Mohs scale

[′mōz ‚skāl]
An empirical scale consisting of 10 minerals with reference to which the hardness of all other minerals is measured; it includes, from softest (designated 1) to hardest (10): talc, gypsum, calcite, fluorite, apatite, orthoclase, quartz, topaz, corundum, and diamond.

Mohs’ Scale


a ten-point scale for measuring the relative hardness of minerals. Proposed by the German scientist F. Mohs in 1811, the scale (see Table 1) comprises ten standards of hardness.

Table 1. Mohs’ scale of hardness

The relative hardness is determined by scratching the surface of the test specimen with a standard of the Mohs’ scale. If, for example, the standard apatite, having a hardness of 5, scratches the specimen and the specimen itself leaves a mark on the surface of fluorite, the standard with a hardness of 4, then the hardness of the mineral being tested is approximately 4.5. Mohs’ scale facilitates the rapid identification of minerals.

References in periodicals archive ?
Rock drillability classification based on the Mohs scale [7]
Rock hardness can be classified two ways: by how many pounds per square inch (psi) of force is required to crush the material, and by the Mohs scale which classifies minerals from 1 (soft) to 10 (hardest).
5 on the Mohs scale, they were much too soft for that label to stick.