Hardness chart of 155 gemstones on the Mohs scale
Key Takeaways
- The hardness of gemstones is an important factor in evaluating the durability and scratch resistance of each type of stone when used in jewelry. People often use the Mohs scale to assess...
The hardness of gemstones is an important factor in evaluating the durability and scratch resistance of each type of stone when used in jewelry. People often use the Mohs scale to assess the hardness of gemstones. Jemmia will share with you information about the hardness of more than 150 gemstones in the article below. Follow along right below!
What is the Mohs hardness scale?
The Mohs hardness scale is a system for measuring the relative hardness of minerals, invented by the German mineralogist Friedrich Mohs in 1812. This scale ranks minerals according to their ability to resist scratching, from 1 (softest) to 10 (hardest).
Meaning of the Mohs gemstone hardness scale
The Mohs hardness scale works based on the scratch resistance of one mineral when it comes into contact with another mineral. It ranks minerals from 1 (softest) to 10 (hardest) based on the phenomenon that a material with higher hardness will scratch a material with lower hardness.
For example:
Quartz (hardness 7) can scratch glass or a steel knife (hardness ~ 5 - 6).
Diamond (hardness 10) can scratch all other minerals.
The hardness of more than 150 common gemstones today
Refer to the hardness table of more than 150 gemstones today:
Note: Hardness is calculated based on the Mohs scale with a maximum value of 10.
Example: Diamond has a hardness of 10/10 on the Mohs scale
Diamond | 10 |
9 | |
Star Ruby | 9 |
9 | |
Star Sapphire | 9 |
8.5 | |
Cat's Eye Alexandrite | 8.5 |
Chrysoberyl | 8.5 |
Cat's Eye Chrysoberyl | 8.5 |
Vanadium Chrysoberyl | 8.5 |
Taaffeite | 8-8.5 |
8 | |
8 | |
Imperial Topaz | 8 |
Pezzotaite | 8 |
7.5-8 | |
Enstatite | 7.5-8 |
Aquamarine | 7.5-8 |
7.5-8 | |
Goshenite Beryl | 7.5-8 |
Golden Beryl | 7.5-8 |
Painite | 7.5-8 |
Phenakite | 7.5-8 |
Red Beryl (Bixbite) | 7.5-8 |
Andalusite | 7.5 |
Euclase | 7.5 |
Grandidierite | 7.5 |
Hambergite | 7.5 |
Dumortierite | 7-8.5 |
Almandine Garnet | 7-7.5 |
Danburite | 7-7.5 |
Iolite | 7-7.5 |
Pyrope Garnet | 7-7.5 |
Spessartite Garnet | 7-7.5 |
Rhodolite Garnet | 7-7.5 |
Color-Change Garnet – color-changing Garnet | 7-7.5 |
Chrome Tourmaline | 7-7.5 |
Malaia Garnet | 7-7.5 |
Paraiba Tourmaline | 7-7.5 |
Rubellite Tourmaline | 7-7.5 |
7-7.5 | |
Uvarovite Garnet | 7-7.5 |
Amethyst | 7 |
7 | |
Ametrine | 7 |
7 | |
Gem Silica | 7 |
Kornerupine | 7 |
Rock Crystal | 7 |
Rose Quartz | 7 |
Smoky Quartz | 7 |
Jeremejevite | 6.5-7.5 |
Sillimanite | 6.5-7.5 |
Zircon | 6.5-7.5 |
6.5-7 | |
Axinite | 6.5-7 |
Bloodstone | 6.5-7 |
6.5-7 | |
Chalcedony | 6.5-7 |
Chrome Chalcedony | 6.5-7 |
Chrysoprase | 6.5-7 |
Demantoid Garnet | 6.5-7 |
Diaspore | 6.5-7 |
Grossular Garnet | 6.5-7 |
Hessonite Garnet | 6.5-7 |
Hiddenite | 6.5-7 |
6.5-7 | |
6.5-7 | |
Mali Garnet | 6.5-7 |
Kunzite | 6.5-7 |
Leuco Garnet | 6.5-7 |
Onyx | 6.5-7 |
6.5-7 | |
Serendibite | 6.5-7 |
Sinhalite | 6.5-7 |
Spodumene | 6.5-7 |
Tanzanite | 6.5-7 |
Tsavorite Garnet | 6.5-7 |
Idocrase (Vesuvianite) | 6.5 |
Cassiterite | 6-7 |
Epidote | 6-7 |
Maw-Sit-Sit | 6-7 |
Unakite | 6-7 |
Amazonite | 6-6.5 |
Andesine | 6-6.5 |
Oligoclase | 6-6.5 |
Benitoite | 6-6.5 |
Labradorite | 6-6.5 |
Moonstone | 6-6.5 |
Nephrite Jade | 6-6.5 |
Orthoclase | 6-6.5 |
Petalite | 6-6.5 |
Prehnite | 6-6.5 |
Scheelite | 6-6.5 |
Sugilite | 6-6.5 |
Sunstone | 6-6.5 |
Zoisite | 6-6.5 |
Amblygonite | 6 |
Clinohumite | 6 |
Hematite | 5.5-6.5 |
Mexican Fire Opal | 5.5-6.5 |
Opal | 5.5-6.5 |
Rhodonite | 5.5-6.5 |
Actinolite | 5.5-6 |
Azurite | 5.5-6 |
Hackmanite | 5.5-6 |
Hauyne | 5.5-6 |
Scapolite | 5.5-6 |
Sodalite | 5.5-6 |
Moldavite | 5.5 |
5-6 | |
Chrome Diopside | 5-6 |
Lapis Lazuli | 5-6 |
Poudretteite | 5-6 |
Turquoise | 5-6 |
Brazilianite | 5.5 |
Datolite | 5-5.5 |
Eudialyte | 5-5.5 |
Obsidian | 5-5.5 |
Sphene (Titanite) | 5-5.5 |
5 | |
Cat's Eye Apatite | 5 |
Dioptase | 5 |
Hemimorphite | 5 |
Smithsonite | 5 |
Charoite | 4.5-5 |
Gaspeite | 4.5-5 |
Larimar | 4.5-5 |
4-7 | |
Bastnasite | 4-5 |
Carletonite | 4-4.5 |
Ammolite (Korite) | 4 |
Fluorite | 4 |
Rhodochrosite | 4 |
Williamsite | 4 |
Aragonite | 3.5-4 |
3.5-4 | |
Cuprite | 3.5-4 |
Malachite | 3.5-4 |
Sphalerite | 3.5-4 |
Coral | 3-4 |
Barite | 3-3.5 |
Celestine | 3-3.5 |
Cerussite | 3-3.5 |
Howlite | 3-3.5 |
Calcite | 3 |
Cobaltocalcite | 3 |
Pearl | 2.5-4.5 |
Jet | 2.5-4 |
Lepidolite | 2.5-3 |
Chrysocolla | 2-4 |
Amber | 2-2.5 |
Cinnabar | 2-2.5 |
Ulexite | 2-2.5 |
The gemstone with the highest hardness on the Mohs scale is diamond (Diamond) with a hardness of 10, which is the hardest known mineral and has the best scratch resistance. In contrast, the gemstone with the lowest hardness is amber (Amber) with a hardness of 2 - 2.5; due to its nature as fossilized tree resin, it is very soft and easily scratched.
How to determine the hardness of a mineral in practice
To determine the hardness of a mineral according to the Mohs scale, you can follow these steps:
Select a mineral sample with known hardness (For example: Gypsum - 2, Quartz - 7).
Use that sample to scratch the surface of the mineral to be tested.
Observe the result:
If the mineral is scratched → it is softer than the mineral used to scratch it.
If the mineral is not scratched → it has hardness equal to or higher than the scratching mineral.
Repeat this process with other minerals to narrow down the hardness range of the sample being tested.
Example:
If a mineral is scratched by a fingernail (hardness ~2.5), it has a hardness <2.5.
If the mineral scratches a coin (hardness ~3.5) but cannot scratch glass (hardness ~5.5), then its hardness may be around 3.5 - 5.5.
Note about the Mohs scale: This scale is only relative and is not an exact measure of material durability.
Example:
The hardness of diamond (10) is not just 1 unit higher than corundum (9); in fact, it is about 4 times harder.
The hardness of corundum (9) is also twice as hard as topaz (8), but topaz is only slightly harder than quartz (7).
Some common gemstones and their hardness on the Mohs scale
Common gemstone name | Hardness (Mohs) | Characteristics of the gemstone |
Diamond (Diamond) | 10 | Hardest, cannot be scratched by other minerals |
Corundum (Ruby, Sapphire) | 9 | Very hard, only scratched by diamond |
Topaz | 8 | Quite durable, easily cracks if subjected to strong impact |
Quartz (Quartz, including Amethyst, Citrine,...) | 7 | Common, good scratch resistance |
Feldspar (Moonstone, Sunstone, Labradorite,...) | 6 - 6.5 | More easily scratched than quartz |
Apatite | 5 | Easily scratched, not common in jewelry |
Fluorite | 4 | Soft, easily broken if not handled carefully |
Amber (Amber) | 2 - 2.5 | Softest, easily scratched |
Diamond is the gemstone with the highest hardness on the Mohs scale, a symbol of eternity and class. With a hardness of 10/10, diamond not only offers absolute scratch resistance but also shines brilliantly, affirming the owner's status. If you are looking for a perfect diamond for wedding rings, jewelry, or investment, explore Jemmia's high-quality diamond collection now.
