Hardness is a gems ability to resist scratching.
Jewelers have been using Mohs hardness scale as a unit of hardness by which to rate gems for many years.
Freidrich Mohs a german gem expert developed the scale way back in 1812.
The scale is a measurement from 1 through 10, where 1 is the most easily scratched and 10 is the most scratch resistant.
Mohs created the scale by selecting 10 natural common minerals and rated them as :-
- Talc
- Gypsum
- Calcite
- Fluorite
- Apatite
- Orthoclase
- Quartz
- Topaz
- Corundum
- Diamond
Each element in the list can scratch an element with a lower number, and be scratched by an element with a higher number.
All gems are compared against this list to determine their hardness.
Toughness is not considered a great deal when buying gems, but maybe it should be.
Toughness is a gems ability to resist breaking (not scratching).
A few surprises are, a diamond is the hardest gem but only has a toughness rating of good.
Jade is easily scratched but has a toughness rating of extreme.
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