What Is The Mohs Hardness Scale?

The Mohs scale of hardness is a scale that ranks minerals by their resistance to scratching or abrasion.

The scale rates minerals on scale from one to ten: with one being the softest and ten being the hardest.

The scale is named after a German mineralogist Friedrich Mohs who introduced it in 1822.

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


Each of these 10 minerals will scratch one with a lower number of hardness or be scratched by one with a higher number on the scale.

The Mohs scale is not linear. What does it mean?

For instance corundum (hardness 9 on the scale) is twice as hard as topaz (hardness 8). However, diamond (hardness 10) is almost four times harder than corundum.

The Mohs scale below includes some common objects added for reference, you can see that for instance talc and gypsum can be scratched by a fingernail, however fingernail will be scratched by a copper coin. On the other hand, quartz (hardness 7) will easily scratch window glass.

mohs scale of hardness poster


Why The Mohs Scale Is Useful When Working With Crystals?


There are two important things the Mohs scale can help you with:

  1. First of all, you will be aware of how delicate any given crystal is. If your crystal is low on the Mohs scale you might consider extra protective measures when storing, moving around, or dusting it.
  1. Knowing your crystal hardness can be useful to determine if it is safe to cleanse it with water (as a general rule crystals with hardness of six or more are safe in water, however there are exceptions and other factors to take into account). Learn more about what crystals cannot be cleansed with water with a handy cheat sheet.

For your convenience below you will find a table with hardness scale for over one hundred crystals. It is in a PDF format, ready to be saved or printed out. Just click on the table :-).

Table with crystals hardness according to Mohs scale

A handy reference guide when working with your crystals and chakras :). To save or print it, just click on it 🙂

How Do You Determine Your Crystal Hardness?


You can use the reference table above and if a crystal is not on the list, you can run your own test.

Simply use as reference a crystal of known hardness and scratch it against a crystal of unknown hardness. If your crystal is for instance of hardness 6 and can scratch the unknown specimen you will know that the specimen is less than 6 Mohs hardness (if it was not scratched by your reference crystal, you will know that it is of a greater than 6 hardness). Now you will need to use more reference crystals of different hardness scales to eventually estimate the hardness of the unknown crystal.

If both scratch one another, their hardness is equal.


When running the hardness test, don’t casually rub one crystal back and forth against another, then looking for a mark. Do it with a single, slow motion and firm pressure. And make sure to place a protective cover over the surface you are using for the test (you don’t want your lovely dining table to be scratched!).


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root chakra affirmations poster framed

Grab your FREE cheat sheet cards with stones for each chakra. A handy reference guide when working with your chakras :).

And before you go to work with your crystals, make sure to grab your FREE chakra printables 🙂

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Copyrights to all above free download posters belong to Your Blissful Self. They are for personal use only and cannot be sold or commercialised in any other way.


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