The Mohs Hardness Scale and Chart for Select Gems
The Mohs hardness scale measures a mineral's resistance to scratching. Find the traditional scale here and a chart of select gems ordered by hardness.
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Understanding Mohs Hardness Scale
The Mohs hardness scale represents one of the most practical and enduring tools in mineralogy and geology, providing a straightforward method for determining a mineral's resistance to scratching or abrasion. Developed in 1812 by German mineralogist Friedrich Mohs, this qualitative ordinal scale ranges from 1 (represented by soft talc) to 10 (represented by diamond, the hardest natural substance). The genius of this system lies in its simplicity—it operates on the fundamental principle that a harder mineral will scratch a softer one, but not vice versa, allowing geologists and gemologists to quickly assess and classify minerals in both laboratory and field settings.
While the Mohs scale is invaluable for mineral identification, it's important to understand its limitations. The scale measures only resistance to scratching, not a mineral's overall durability or toughness against impacts. This distinction is crucial—some minerals with high Mohs hardness can be quite brittle and break easily when struck (like diamond), while softer minerals might better withstand impacts without fracturing. The scale is also not linear, meaning the difference in absolute hardness between consecutive numbers varies significantly—the jump from corundum (9) to diamond (10) represents a much greater increase in actual hardness than the difference between talc (1) and gypsum (2). Despite these limitations, the scale's practical utility has ensured its continued relevance in mineralogy, gemology, and materials science for over two centuries, serving as a first-line method for understanding how minerals resist being scratched.
The Mohs Hardness Scale
| 10 | Diamond |
| 9 | Corundum |
| 8 | Topaz |
| 7 | Quartz |
| 6 | Feldspar |
| 5 | Apatite |
| 4 | Fluorite |
| 3 | Calcite |
| 2 | Gypsum |
| 1 | Talc |
Select Gems Ordered By Mohs Hardness
| Name | Hardness | Name | Hardness |
| Diamond | 10 | Hypersthene | 5 - 6 |
| Synth. Moissanit | 9½ | Ilmenite | 5 - 6 |
| Ruby | 9 | Lapis Lazuli | 5 - 6 |
| Sapphire | 9 | Lazulite | 5 - 6 |
| Alexandrite | 8½ | Nepheline | 5 - 6 |
| Chrysoberyll | 8½ | Neptunite | 5 - 6 |
| Holtite | 8½ | Pargasite | 5 - 6 |
| YAG | 8½ | Richterite | 5 - 6 |
| Zirconia | 8½ | Samarskite | 5 - 6 |
| Rhodizite | 8 - 8½ | Stibiotantalite | 5 - 6 |
| Taafeite | 8 - 8½ | Tremolite | 5 - 6 |
| Spinel | 8 | Turquoise | 5 - 6 |
| Topaz | 8 | Analcime | 5 - 5½ |
| Aquamarine | 7½ - 8 | Datolite | 5 - 5½ |
| Red Beryl | 7½ - 8 | Durangite | 5 - 5½ |
| Precious Beryl | 7½ - 8 | Eudialyte | 5 - 5½ |
| Gahnite | 7½ - 8 | Goethite | 5 - 5½ |
| Galaxite | 7½ - 8 | Herderite | 5 - 5½ |
| Painite | 7½ - 8 | Hydroxylherderite | 5 - 5½ |
| Phenakite | 7½ - 8 | Meliphanite | 5 - 5½ |
| Emerald | 7½ - 8 | Mesolite | 5 - 5½ |
| Andalusite | 7½ | Microlite | 5 - 5½ |
| Euclase | 7½ | Monazite | 5 - 5½ |
| Hambergite | 7½ | Natrolite | 5 - 5½ |
| Sapphirine | 7½ | Nickeline | 5 - 5½ |
| Dumortierite | 7 - 8½ | Papagoite | 5 - 5½ |
| Almandine | 7 - 7½ | Psilomelane | 5 - 5½ |
| Boracite | 7 - 7½ | Scolecite | 5 - 5½ |
| Cordierite | 7 - 7½ | Sellaite | 5 - 5½ |
| Danburite | 7 - 7½ | Thomsonite | 5 - 5½ |
| Grandidierite | 7 - 7½ | Titanite | 5 - 5½ |
| Pyrope | 7 - 7½ | Wolframite | 5 - 5½ |
| Schorlomite | 7 - 7½ | Yttrotantalite | 5 - 5½ |
| Sekaninaite | 7 - 7½ | Apatite | 5 |
| Simpsonite | 7 - 7½ | Bismutotantalite | 5 |
| Spessartine | 7 - 7½ | Childrenite | 5 |
| Staurolite | 7 - 7½ | Chlorapatite | 5 |
| Turmaline | 7 - 7½ | Dioptase | 5 |
| Uvarovite | 7 - 7½ | Eosphorite | 5 |
| Amethyst | 7 | Flourapatite | 5 |
| Aventurine | 7 | Hemimorphite | 5 |
| Rock Crystal | 7 | Hydroxylapatite | 5 |
| Chambersite | 7 | Mangan-Apatite | 5 |
| Chromdravite | 7 | Odontolite | 5 |
| Citrine | 7 | Rinkite | 5 |
| Forsterite | 7 | Schlossmacherite | 5 |
| Povondraite | 7 | Smithsonite | 5 |
| Quartz | 7 | Spurrite | 5 |
| Smoky Quartz | 7 | Strass | 5 |
| Zunyite | 7 | Vayrynenite | 5 |
| Garnet | 6½ - 7½ | Ekanite | 4½ - 6½ |
| Jeremejevite | 6½ - 7½ | Apophyllite | 4½ - 5 |
| Sillimanite | 6½ - 7½ | Augelite | 4½ - 5 |
| Zircon | 6½ - 7½ | Charoite | 4½ - 5 |
| Axinite | 6½ - 7 | Gaspéite | 4½ - 5 |
| Chalcedony | 6½ - 7 | Hodgkinsonite | 4½ - 5 |
| Chrysoprase | 6½ - 7 | Legrandite | 4½ - 5 |
| Diaspore | 6½ - 7 | Pectolite | 4½ - 5 |
| Ferro-Axinite | 6½ - 7 | Scheelite | 4½ - 5 |
| Gadolinite | 6½ - 7 | Wardite | 4½ - 5 |
| Grossular | 6½ - 7 | Wollastonite | 4½ - 5 |
| Hiddenite | 6½ - 7 | Bayldonite | 4½ |
| Jadeite | 6½ - 7 | Colemanite | 4½ |
| Jasper | 6½ - 7 | Parisite | 4½ |
| Kornerupine | 6½ - 7 | Prosopite | 4½ |
| Kunzite | 6½ - 7 | Yugawaralite | 4½ |
| Mangan-Axinite | 6½ - 7 | Kyanite | 4 - 7 |
| Peridot | 6½ - 7 | Sérandite | 4 - 5½ |
| Pollucite | 6½ - 7 | Chabazite | 4 - 5 |
| Serendibite | 6½ - 7 | Friedelite | 4 - 5 |
| Sinhalite | 6½ - 7 | Lithiophilite | 4 - 5 |
| Spodumene | 6½ - 7 | Mordenite | 4 - 5 |
| Tanzanite | 6½ - 7 | Triphylite | 4 - 5 |
| Thorianite | 6½ - 7 | Variscite | 4 - 5 |
| Tinzenite | 6½ - 7 | Zincite | 4 - 5 |
| GGG | 6½ | Carletonite | 4 - 4½ |
| Magnesio-Axinite | 6½ | Hübnerite | 4 - 4½ |
| Nambulite | 6½ | Purpurite | 4 - 4½ |
| Vesuvianite | 6½ | Algodonite | 4 |
| Cassiterite | 6 - 7 | Ammonite | 4 |
| Clinozoisite | 6 - 7 | Barytocalcite | 4 |
| Epidote | 6 - 7 | Flourite | 4 |
| Hancockite | 6 - 7 | Leucophanite | 4 |
| Pyrolusite | 6 - 7 | Libethenite | 4 |
| Sogdianite | 6 - 7 | Rhodochrosite | 4 |
| Amazonite | 6 - 6½ | Magnesite | 3½ - 4½ |
| Andesine | 6 - 6½ | Siderite | 3½ - 4½ |
| Anorthoclase | 6 - 6½ | Ankerite | 3½ - 4 |
| Benitoite | 6 - 6½ | Aragonite | 3½ - 4 |
| Bixbyite | 6 - 6½ | Azurite | 3½ - 4 |
| Bytownite | 6 - 6½ | Chalcopyrite | 3½ - 4 |
| Chondroite | 6 - 6½ | Creedite | 3½ - 4 |
| Helvite | 6 - 6½ | Cuprite | 3½ - 4 |
| Hyalophane | 6 - 6½ | Dickinsonite | 3½ - 4 |
| Labradorite | 6 - 6½ | Dolomite | 3½ - 4 |
| Marcasite | 6 - 6½ | Euchroite | 3½ - 4 |
| Microcline | 6 - 6½ | Langbeinite | 3½ - 4 |
| Nephrite | 6 - 6½ | Malachite | 3½ - 4 |
| Norbergite | 6 - 6½ | Mimetite | 3½ - 4 |
| Oligoclase | 6 - 6½ | Pentlandite | 3½ - 4 |
| Petalite | 6 - 6½ | Powellite | 3½ - 4 |
| Prehnite | 6 - 6½ | Scorodite | 3½ - 4 |
| Pyrite | 6 - 6½ | Shungite | 3½ - 4 |
| Rutile | 6 - 6½ | Shattuckite | 3½ - 4 |
| Sanidine | 6 - 6½ | Sphalerite | 3½ - 4 |
| Smaragdite | 6 - 6½ | Wavellite | 3½ - 4 |
| Sugilite | 6 - 6½ | Wurtzite | 3½ - 4 |
| Tantalite | 6 - 6½ | Adamite | 3½ |
| Xonotlite | 6 - 6½ | Anhydrite | 3½ |
| Zoisite | 6 - 6½ | Chiolite | 3½ |
| Aegirine | 6 | Huréaulite | 3½ |
| Amblygonite | 6 | Strontianite | 3½ |
| Clinohumite | 6 | Thaumasite | 3½ |
| Humite | 6 | Weloganite | 3½ |
| Hurlbutite | 6 | Cacoxenite | 3 -4 |
| Lawsonite | 6 | Coral | 3 -4 |
| Pumpellyite | 6 | Ludlamite | 3 -4 |
| Tephroite | 6 | Anglesite | 3 - 3½ |
| Vlasovite | 6 | Baryte | 3 - 3½ |
| Zektzerite | 6 | Boleite | 3 - 3½ |
| Hematite | 5½ - 6½ | Cerussite | 3 - 3½ |
| Hedenbergite | 5½ - 6½ | Celestine | 3 - 3½ |
| Magnetite | 5½ - 6½ | Descloizite | 3 - 3½ |
| Manganotantalite | 5½ - 6½ | Greenockite | 3 - 3½ |
| Opal | 5½ - 6½ | Howlite | 3 - 3½ |
| Rhodonite | 5½ - 6½ | Millerite | 3 - 3½ |
| Actinolite | 5½ - 6 | Phosphophyllite | 3 - 3½ |
| Allanite | 5½ - 6 | Witherite | 3 - 3½ |
| Anatase | 5½ - 6 | Bornite | 3 |
| Beryllonite | 5½ - 6 | Calcite | 3 |
| Brookite | 5½ - 6 | Kurnakovite | 3 |
| Bustamite | 5½ - 6 | Shortite | 3 |
| Canasite | 5½ - 6 | Wulfenite | 3 |
| Cobaltite | 5½ - 6 | Serpentine | 2½ - 5½ |
| Euxenite | 5½ - 6 | Pearl | 2½ - 4½ |
| Fabulite | 5½ - 6 | Jet | 2½ - 4 |
| Fergusonite | 5½ - 6 | Chalcocite | 2½ - 3 |
| Haüyne | 5½ - 6 | Crocoite | 2½ - 3 |
| Leucite | 5½ - 6 | Gaylussite | 2½ - 3 |
| Marialite | 5½ - 6 | Gold | 2½ - 3 |
| Meionite | 5½ - 6 | Inderite | 2½ - 3 |
| Milarite | 5½ - 6 | Lepidolite | 2½ - 3 |
| Montebrasite | 5½ - 6 | Pyrargyrite | 2½ - 3 |
| Natromontebrasite | 5½ - 6 | Silver | 2½ - 3 |
| Periclase | 5½ - 6 | Stolzite | 2½ - 3 |
| Pyroxmangite | 5½ - 6 | Vanadinite | 2½ - 3 |
| Sarcolite | 5½ - 6 | Whewellite | 2½ - 3 |
| Scorzalite | 5½ - 6 | Brucite | 2½ |
| Scapolite | 5½ - 6 | Cryolite | 2½ |
| Sodalite | 5½ - 6 | Linarite | 2½ |
| Tugtupite | 5½ - 6 | Lizardite | 2½ |
| Brazilianite | 5½ | Proustite | 2½ |
| Breithauptite | 5½ | Sturmanite | 2½ |
| Chromite | 5½ | Chrysocolla | 2 - 4 |
| Enstatite | 5½ | Clinochrysotile | 2 -3 |
| Linobate | 5½ | Fuchsite | 2 -3 |
| Magnesiochromite | 5½ | Muscovite | 2 -3 |
| Moldavite | 5½ | Phosgenite | 2 -3 |
| Willemite | 5½ | Shomiokite | 2 -3 |
| Aeschynite | 5 - 6 | Amber | 2 - 2½ |
| Bronzite | 5 - 6 | Cinnabar | 2 - 2½ |
| Cancrinite | 5 - 6 | Ettringite | 2 - 2½ |
| Catapleiite | 5 - 6 | Kämmererite | 2 - 2½ |
| Ceruléite | 5 - 6 | Mellite | 2 - 2½ |
| Clinoenstatite | 5 - 6 | Senarmontite | 2 - 2½ |
| Davidite | 5 - 6 | Ulexite | 2 - 2½ |
| Diopside | 5 - 6 | Villiaumite | 2 - 2½ |
| Ferrosilite | 5 - 6 | Gypsum | 2 |
| Hornblende | 5 - 6 | Stichtite | 1½ - 2½ |
| Sulphur | 1½ - 2½ | ||
| Covellite | 1½ - 2 | ||
| Melonite | 1½ - 2 | ||
| Realgar | 1½ - 2 | ||
| Vivianite | 1½ - 2 | ||
| Palygorskite | 1 - 2 | ||
| Pyrophyllite | 1 - 2 | ||
| Talc | 1 |
Source: Gemstones of the World, 3rd Edition, Walter Schumann.
International Gem Society
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