Hardest Minerals
20 minerals
The hardest minerals are dominated by covalently bonded structures. Diamond (10) owes its supreme hardness to a three-dimensional network of sp³ carbon–carbon bonds, while corundum (9) derives strength from tightly packed aluminium and oxygen atoms in a hexagonal close-packed arrangement. Topaz, chrysoberyl, and spinel round out the upper tier with robust ionic-covalent bonding.
These ultra-hard minerals have enormous industrial value. Diamond is the benchmark abrasive in cutting tools and drill bits, corundum (as ruby and sapphire) finds use in watch bearings and laser components, and spinel serves as a refractory ceramic in high-temperature furnaces.
How we ranked these
Ranked by maximum Mohs hardness value. Values from Mindat.org and the Handbook of Mineralogy. Only minerals with verified hardness data are included.
Cubic (Isometric) · Adamantine
Diamond is the hardest known natural material, composed of pure carbon arranged in an isometric crystal structure. Formed deep in Earth's mantle under extreme pressure and temperature, diamonds are br
Trigonal · Adamantine
Corundum is the second hardest natural mineral after diamond. Its gem varieties are ruby (red, colored by chromium) and sapphire (all other colors). Synthetic corundum is widely used as an abrasive an
Hexagonal · Vitreous
Beryl is a beryllium aluminum cyclosilicate with several gem varieties: emerald (green, colored by chromium), aquamarine (blue), morganite (pink), heliodor (yellow), and goshenite (colorless). Emerald
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Spinel (MgAl2O4)Cubic (Isometric) · Vitreous
Spinel is a magnesium aluminum oxide that forms beautiful crystals highly valued as gemstones. Many famous historical rubies, including the Black Prince's Ruby in the British Crown Jewels, are actuall
Mohs 7.5-8.0 SG 3.58-3.61 VitreousSee details → -
Topaz (Al2SiO4(F,OH)2)Orthorhombic · Vitreous
Topaz is the reference mineral for hardness 8 on the Mohs scale. It forms in granite and pegmatite veins and is prized as a gemstone. Imperial topaz (orange-pink) from Ouro Preto, Brazil, is the most
Mohs 8.0 SG 3.49-3.57 VitreousSee details → -
Garnet (Almandine) (Fe3Al2(SiO4)3)Cubic (Isometric) · Vitreous
grupo Almandine is the most common garnet species and a key metamorphic indicator mineral. The garnet group includes pyrope, grossular, andradite, spessartine, and uvarovite. Garnets are widely used a
Mohs 6.5-7.5 SG 3.93-4.32 VitreousSee details → -
Staurolite (Fe2Al9Si4O23(OH))Monoclinic · Vitreous
Staurolite is famous for its cruciform twinned crystals, which form cross-shaped penetration twins. These natural crosses have been collected as good luck charms for centuries. It is an important meta
Mohs 7.0-7.5 SG 3.65-3.77 VitreousSee details → -
Tourmaline (Complex borosilicate)Trigonal · Vitreous
grupo Tourmaline is a group of complex borosilicate minerals famous for their wide range of colors. Watermelon tourmaline shows pink centers with green rims. The most common variety, schorl (black), a
Mohs 7.0-7.5 SG 2.82-3.32 VitreousSee details → -
Zircon (ZrSiO4)Tetragonal · Adamantine
Zircon is the oldest mineral found on Earth, with some crystals dating back 4.4 billion years. It is an important accessory mineral in igneous rocks and a key mineral for geochronology (U-Pb dating).
Mohs 6.5-7.5 SG 3.93-4.73 AdamantineSee details → -
Cassiterite (SnO2)Tetragonal · Adamantine
Cassiterite is the principal ore of tin and has been mined since the Bronze Age. It occurs primarily in high-temperature hydrothermal veins and placer deposits. Major sources include China, Indonesia,
Mohs 6.0-7.0 SG 6.80-7.10 AdamantineSee details → -
Epidote (Ca2(Al,Fe)3(SiO4)(Si2O7)O(OH))Monoclinic · Vitreous
Epidoto é um mineral metamórfico e hidrotermal comum, reconhecível por seu pleocroísmo verde-amarelado a verde-escuro.
Mohs 6.0-7.0 SG 3.25-3.50 VitreousSee details → -
Kyanite (Al2SiO5)Triclinic · Vitreous
Silicato de alumínio polimórfico, notável por dureza variável dependendo da direção do cristal. Comum em rochas metamórficas de alta pressão, especialmente em xistos alumínio-ricos. Frequentemente ass
Mohs 4.5-7.0 SG 3.53-3.65 VitreousSee details → -
Olivine ((Mg,Fe)2SiO4)Orthorhombic · Vitreous
Olivina é um grupo de minerais silicatados comuns no manto terrestre e em rochas máficas e ultramáficas.
Mohs 6.5-7.0 SG 3.22-4.39 VitreousSee details → -
Quartz (SiO2)Trigonal · Vitreous
Quartz is the second most abundant mineral in Earth's continental crust, after feldspar. It occurs in virtually every geological environment and is a component of almost every rock type. Varieties inc
Mohs 7.0 SG 2.65 VitreousSee details → -
Amazonite (KAlSi3O8)Triclinic · Vitreous
Amazonite is a green to blue-green variety of microcline feldspar. Its color is attributed to trace amounts of lead and water in the crystal structure. Despite its name, it has never been found in the
Mohs 6.0-6.5 SG 2.56-2.58 VitreousSee details → -
Feldspar (Orthoclase) (KAlSi3O8)Monoclinic · Vitreous
Orthoclase é um feldspato potássico e um dos minerais mais comuns da crosta terrestre. É um componente essencial do granito e de muitas outras rochas ígneas. A pedra da lua é uma variedade gemológica
Mohs 6.0-6.5 SG 2.55-2.63 VitreousSee details → -
Hematite (Fe2O3)Trigonal · Metallic
Hematite is the principal ore of iron and one of the most common iron minerals. Its name comes from the Greek word for blood, referring to the red color of its streak. Specular hematite has a brillian
Mohs 5.0-6.5 SG 5.00-5.30 MetallicSee details → -
Labradorite ((Ca,Na)(Al,Si)4O8)Triclinic · Vitreous
Labradorite is a plagioclase feldspar famous for its spectacular display of iridescent colors called labradorescence. When light enters the stone, it is reflected from internal structures, producing f
Mohs 6.0-6.5 SG 2.68-2.72 VitreousSee details → -
Magnetite (Fe3O4)Cubic (Isometric) · Metallic
Magnetita é um dos minerais mais magnéticos de todos os minerais naturais e é a principal fonte de minério de ferro.
Mohs 5.5-6.5 SG 5.17-5.18 MetallicSee details → -
Pyrite (FeS2)Cubic (Isometric) · Metallic
Conhecida como 'ouro dos tolos', a pirita é o mineral sulfeto mais comum. Seu brilho metálico e cor amarelo-latão pálido lhe conferem uma semelhança superficial com o ouro. Ocorre em todos os tipos de
Mohs 6.0-6.5 SG 4.95-5.10 MetallicSee details →