Mohs hardness degree of hardness divided by ten: 1, talc, 2, 3 gypsum, calcite 4, 5 fluorite, apatite 6, 7 orthoclase, quartz 8 9 topaz, corundum 10 diamonds.
The difference between the levels of hardness are not equal, only that the relative size between the hardness level.
Select the location of the sample is sharp. In the known mineral hardness durometer planar plane characterization, hardness test scored from low to high in turn. Whether the observed hardness flat facets, graze the surface to prevent powder left on the sample hardness, making misjudgments.