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This article was created in an effort to answer one of the most frequently asked questions we receive at the gem and mineral shows. What is the harness of this stone? How can I tell what the hardness of a stone is? We are hopeful that this article answers those questions and that you will come back to reference this page for any questions you may have as you grow your mineral collection!
Wikipedia defines the Mohs scale of mineral hardness as a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of minerals through the ability of harder material to scratch softer material.
The scale was introduced in 1812 by the German geologist and mineralogist Friedrich Mohs, in his book “Versuch einer Elementar-Methode zur naturhistorischen Bestimmung und Erkennung der Fossilien”. it is one of several definitions of hardness in materials science, some of which are more quantitative.
The method of comparing hardness by observing which minerals can scratch others is of great antiquity, having been mentioned by Theophrastus in his treatise On Stones, c. 300 BC, followed by Pliny the Elder in his Naturalis Historia, c. AD 77. The Mohs scale is useful for identification of minerals in the field.
6. Feldspar
7. Quartz
8. Topaz
9. Corundum
10. Diamond
To test the hardness of a specimen take it and try to scratch it with the first rock in the Mohs Hardness Scale (Talc). If it is scratched then the rock you’re testing is hardness 1. If not then try to scratch the Talc with your rock. If the rock scratches the Talc then it is harder than the Talc. The hardness of the rock that scratches your specimen is the hardness of your specimen.
If you are not comfortable scratching your specimen, below is a listing of gemstones and their hardness according to the International Gem Society.
Name Hardness
Diamond 10
Synth. Moissanit 9½
Ruby 9
Sapphire 9
Alexandrite 8½
Chrysoberyll 8½
Holtite 8½
YAG 8½
Zirconia 8½
Rhodizite 8 – 8½
Taafeite 8 – 8½
Spinel 8
Topaz 8
Aquamarine 7½ – 8
Red Beryl 7½ – 8
Precious Beryl 7½ – 8
Gahnite 7½ – 8
Galaxite 7½ – 8
Painite 7½ – 8
Phenakite 7½ – 8
Emerald 7½ – 8
Andalusite 7½
Euclase 7½
Hambergite 7½
Sapphirine 7½
Dumortierite 7 – 8½
Almandine 7 – 7½
Boracite 7 – 7½
Cordierite 7 – 7½
Danburite 7 – 7½
Grandidierite 7 – 7½
Pyrope 7 – 7½
Schorlomite 7 – 7½
Sekaninaite 7 – 7½
Simpsonite 7 – 7½
Spessartine 7 – 7½
Staurolite 7 – 7½
Tourmaline 7 – 7½
Uvarovite 7 – 7½
Amethyst 7
Aventurine 7
Rock Crystal 7
Chambersite 7
Chromdravite 7
Citrine 7
Forsterite 7
Povondraite 7
Quartz 7
Smoky Quartz 7
Zunyite 7
Garnet 6½ – 7½
Jeremejevite 6½ – 7½
Sillimanite 6½ – 7½
Zircon 6½ – 7½
Axinite 6½ – 7
Chalcedony 6½ – 7
Chrysoprase 6½ – 7
Diaspore 6½ – 7
Ferro-Axinite 6½ – 7
Gadolinite 6½ – 7
Grossular 6½ – 7
Hiddenite 6½ – 7
Jadeite 6½ – 7
Jasper 6½ – 7
Kornerupine 6½ – 7
Kunzite 6½ – 7
Mangan-Axinite 6½ – 7
Peridot 6½ – 7
Pollucite 6½ – 7
Serendibite 6½ – 7
Sinhalite 6½ – 7
Spodumene 6½ – 7
Tanzanite 6½ – 7
Thorianite 6½ – 7
Tinzenite 6½ – 7
GGG 6½
Magnesio-Axinite 6½
Nambulite 6½
Vesuvianite 6½
Cassiterite 6 – 7
Clinozoisite 6 – 7
Epidote 6 – 7
Hancockite 6 – 7
Pyrolusite 6 – 7
Sogdianite 6 – 7
Amazonite 6 – 6½
Andesine 6 – 6½
Anorthoclase 6 – 6½
Benitoite 6 – 6½
Bixbyite 6 – 6½
Bytownite 6 – 6½
Chondroite 6 – 6½
Helvite 6 – 6½
Hyalophane 6 – 6½
Labradorite 6 – 6½
Marcasite 6 – 6½
Microcline 6 – 6½
Nephrite 6 – 6½
Norbergite 6 – 6½
Oligoclase 6 – 6½
Petalite 6 – 6½
Prehnite 6 – 6½
Pyrite 6 – 6½
Rutile 6 – 6½
Sanidine 6 – 6½
Smaragdite 6 – 6½
Sugilite 6 – 6½
Tantalite 6 – 6½
Xonotlite 6 – 6½
Zoisite 6 – 6½
Aegirine 6
Amblygonite 6
Clinohumite 6
Humite 6
Hurlbutite 6
Lawsonite 6
Pumpellyite 6
Tephroite 6
Vlasovite 6
Zektzerite 6
Hematite 5½ – 6½
Hedenbergite 5½ – 6½
Magnetite 5½ – 6½
Manganotantalite 5½ – 6½
Opal 5½ – 6½
Rhodonite 5½ – 6½
Actinolite 5½ – 6
Allanite 5½ – 6
Anatase 5½ – 6
Beryllonite 5½ – 6
Brookite 5½ – 6
Bustamite 5½ – 6
Canasite 5½ – 6
Cobaltite 5½ – 6
Euxenite 5½ – 6
Fabulite 5½ – 6
Fergusonite 5½ – 6
Haüyne 5½ – 6
Leucite 5½ – 6
Marialite 5½ – 6
Meionite 5½ – 6
Milarite 5½ – 6
Montebrasite 5½ – 6
Natromontebrasite 5½ – 6
Periclase 5½ – 6
Pyroxmangite 5½ – 6
Sarcolite 5½ – 6
Scorzalite 5½ – 6
Scapolite 5½ – 6
Sodalite 5½ – 6
Tugtupite 5½ – 6
Brazilianite 5½
Breithauptite 5½
Chromite 5½
Enstatite 5½
Linobate 5½
Magnesiochromite 5½
Moldavite 5½
Willemite 5½
Aeschynite 5 – 6
Bronzite 5 – 6
Cancrinite 5 – 6
Catapleiite 5 – 6
Ceruléite 5 – 6
Clinoenstatite 5 – 6
Davidite 5 – 6
Diopside 5 – 6
Ferrosilite 5 – 6
Hornblende 5 – 6
Name Hardness
Hypersthene 5 – 6
Ilmenite 5 – 6
Lapis Lazuli 5 – 6
Lazulite 5 – 6
Nepheline 5 – 6
Neptunite 5 – 6
Pargasite 5 – 6
Richterite 5 – 6
Samarskite 5 – 6
Stibiotantalite 5 – 6
Tremolite 5 – 6
Turquoise 5 – 6
Analcime 5 – 5½
Datolite 5 – 5½
Durangite 5 – 5½
Eudialyte 5 – 5½
Goethite 5 – 5½
Herderite 5 – 5½
Hydroxylherderite 5 – 5½
Meliphanite 5 – 5½
Mesolite 5 – 5½
Microlite 5 – 5½
Monazite 5 – 5½
Natrolite 5 – 5½
Nickeline 5 – 5½
Papagoite 5 – 5½
Psilomelane 5 – 5½
Scolecite 5 – 5½
Sellaite 5 – 5½
Thomsonite 5 – 5½
Titanite 5 – 5½
Wolframite 5 – 5½
Yttrotantalite 5 – 5½
Apatite 5
Bismutotantalite 5
Childrenite 5
Chlorapatite 5
Dioptase 5
Eosphorite 5
Flourapatite 5
Hemimorphite 5
Hydroxylapatite 5
Mangan-Apatite 5
Odontolite 5
Rinkite 5
Schlossmacherite 5
Smithsonite 5
Spurrite 5
Strass 5
Vayrynenite 5
Ekanite 4½ – 6½
Apophyllite 4½ – 5
Augelite 4½ – 5
Charoite 4½ – 5
Gaspéite 4½ – 5
Hodgkinsonite 4½ – 5
Legrandite 4½ – 5
Pectolite 4½ – 5
Scheelite 4½ – 5
Wardite 4½ – 5
Wollastonite 4½ – 5
Bayldonite 4½
Colemanite 4½
Parisite 4½
Prosopite 4½
Yugawaralite 4½
Kyanite 4 – 7
Sérandite 4 – 5½
Chabazite 4 – 5
Friedelite 4 – 5
Lithiophilite 4 – 5
Mordenite 4 – 5
Triphylite 4 – 5
Variscite 4 – 5
Zincite 4 – 5
Carletonite 4 – 4½
Hübnerite 4 – 4½
Purpurite 4 – 4½
Algodonite 4
Ammonite 4
Barytocalcite 4
Flourite 4
Leucophanite 4
Libethenite 4
Rhodochrosite 4
Magnesite 3½ – 4½
Siderite 3½ – 4½
Ankerite 3½ – 4
Aragonite 3½ – 4
Azurite 3½ – 4
Chalcopyrite 3½ – 4
Creedite 3½ – 4
Cuprite 3½ – 4
Dickinsonite 3½ – 4
Dolomite 3½ – 4
Euchroite 3½ – 4
Langbeinite 3½ – 4
Malachite 3½ – 4
Mimetite 3½ – 4
Pentlandite 3½ – 4
Powellite 3½ – 4
Scorodite 3½ – 4
Shungite 3½ – 4
Shattuckite 3½ – 4
Sphalerite 3½ – 4
Wavellite 3½ – 4
Wurtzite 3½ – 4
Adamite 3½
Anhydrite 3½
Chiolite 3½
Huréaulite 3½
Strontianite 3½
Thaumasite 3½
Weloganite 3½
Cacoxenite 3 -4
Coral 3 -4
Ludlamite 3 -4
Anglesite 3 – 3½
Baryte 3 – 3½
Boleite 3 – 3½
Cerussite 3 – 3½
Celestine 3 – 3½
Descloizite 3 – 3½
Greenockite 3 – 3½
Howlite 3 – 3½
Millerite 3 – 3½
Phosphophyllite 3 – 3½
Witherite 3 – 3½
Bornite 3
Calcite 3
Kurnakovite 3
Shortite 3
Wulfenite 3
Serpentine 2½ – 5½
Pearl 2½ – 4½
Jet 2½ – 4
Chalcocite 2½ – 3
Crocoite 2½ – 3
Gaylussite 2½ – 3
Gold 2½ – 3
Inderite 2½ – 3
Lepidolite 2½ – 3
Pyrargyrite 2½ – 3
Silver 2½ – 3
Stolzite 2½ – 3
Vanadinite 2½ – 3
Whewellite 2½ – 3
Brucite 2½
Cryolite 2½
Linarite 2½
Lizardite 2½
Proustite 2½
Sturmanite 2½
Chrysocolla 2 – 4
Clinochrysotile 2 -3
Fuchsite 2 -3
Muscovite 2 -3
Phosgenite 2 -3
Shomiokite 2 -3
Amber 2 – 2½
Cinnabar 2 – 2½
Ettringite 2 – 2½
Kämmererite 2 – 2½
Mellite 2 – 2½
Senarmontite 2 – 2½
Ulexite 2 – 2½
Villiaumite 2 – 2½
Gypsum 2
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
