Mohs scale of mineral hardness

Mohs scale of mineral hardness is a list of ten minerals in ascending order of hardness. Each mineral listed will scratch the minerals numerically lower than it on the scale. It is one of various lists defining hardness in materials science.^[1] It lacks precision but is extremely useful for field geologists.^[1]

The list was developed by geologist and mineralogist Friedrich Mohs in 1812.^[1] However, human beings have been assessing hardness for even longer through seeing which minerals scratched which, back to antiquity.^[1]

Soft metals are usually considered to be those beneath the hardness of 6 in the list (namely 1 to 5).

"Scratching" is determined to be a "non-elastic dislocation[...] visible to the naked eye".^[1]

1. Talc
2. Gypsum
3. Calcite
4. Fluorite
5. Apatite
6. Orthoclase feldspar
7. Quartz
8. Topaz
9. Corundum
10. Diamond

[Edit note: If someone has the time and inclination, it'd be helpful to repeat a similar pictorial table shown in Wikipedia's article on this topic.]