Gemstone Hardness List

Mohs hardness values for more than 140 gemstones and gem materials, from talc at 1 to diamond at 10, with the mineral species behind each trade name.

Published 6 Aug 20262 min read4 sections147 entries

Painterly rendering of Friedrich Mohs in his study working on his hardness scale, with the ten labelled reference minerals set out in front of him

2 min read4 sections147 entries

The Mohs scale measures resistance to scratching, not resistance to breaking or chipping. The values below are standard ranges for natural gemstones and commonly used gem materials, listed alphabetically by the name the stone is sold under, with its mineral group and chemical formula.

For the background behind these numbers, how the scale was devised, why its steps are so uneven, and whether anything is genuinely harder than diamond, see our companion article on the hardness of crystals and gemstones.

What is the Mohs hardness of gemstones?

The Mohs scale ranks gemstones from 1 to 10 by how well they resist scratching. Diamond is 10, ruby and sapphire 9, topaz and spinel 8, and quartz 7. Stones below 7 slowly lose their polish in everyday wear, so they suit earrings and pendants better than rings.

How to read this list

Most entries give a range instead of a single figure. That is normal: hardness varies with composition, with the direction the crystal is tested in, with weathering, and with whether the material is a single crystal, an aggregate, a rock, or a composite. Kyanite is the clearest case in this list, measuring roughly 4.5 to 5 along the length of a blade but 6.5 to 7 across it, so both figures are given.

One value is worth remembering above the others: 7, the hardness of quartz. Ordinary dust contains fine quartz particles, so anything below 7 gradually dulls with daily wear. Stones at 7 and above hold a polish far longer in rings and bracelets, while softer material is better suited to earrings, pendants, and display pieces.

Gemstone hardness table

The table below brings together more than 140 gemstones and gem minerals with their mineral group, chemical formula and Mohs hardness. Hardness is not one fixed number: many crystals are harder along one axis than another, so a stone can resist scratching better on one face than on the next.
Mineral	Mineral group	Formula	Mohs hardness
Agate	Quartz	SiO₂	6.5-7
Alexandrite	Chrysoberyl	BeAl₂O₄	8.5
Almandine	Garnet	Fe₃Al₂(SiO₄)₃	7-7.5
Amazonite	Feldspar	KAlSi₃O₈	6-6.5
Amber	Organic	Fossil resin (C, H, O)	2-2.5
Amblygonite-Montebrasite	Amblygonite	LiAl(PO₄)(F,OH)	5.5-6
Amethyst	Quartz	SiO₂	7
Ametrine	Quartz	SiO₂	7
Ammolite	Organic	CaCO₃	3.5
Andalusite	Andalusite	Al₂SiO₅	6.5-7.5
Andradite	Garnet	Ca₃Fe₂(SiO₄)₃	6.5-7
Apatite	Apatite	Ca₅(PO₄)₃(F,Cl,OH)	5
Aquamarine	Beryl	Be₃Al₂Si₆O₁₈	7.5-8
Aragonite	Aragonite	CaCO₃	3.5-4
Aventurine quartz	Quartz	SiO₂	7
Axinite	Axinite	Ca₂(Fe,Mn,Mg)Al₂BSi₄O₁₅(OH)	6.5-7
Azurite	Azurite	Cu₃(CO₃)₂(OH)₂	3.5-4
Bastnäsite	Bastnäsite	(Ce,La)(CO₃)F	4-4.5
Benitoite	Benitoite	BaTiSi₃O₉	6-6.5
Beryl	Beryl	Be₃Al₂Si₆O₁₈	7.5-8
Beryllonite	Beryllonite	NaBePO₄	5.5-6
Bloodstone	Quartz	SiO₂	6.5-7
Brazilianite	Brazilianite	NaAl₃(PO₄)₂(OH)₄	5.5
Bronzite	Pyroxene	(Mg,Fe)SiO₃	5-6
Calcite	Calcite	CaCO₃	3
Carnelian	Quartz	SiO₂	6.5-7
Cassiterite	Rutile	SnO₂	6-7
Cat's-eye chrysoberyl	Chrysoberyl	BeAl₂O₄	8.5
Chalcedony	Quartz	SiO₂	6.5-7
Charoite	Charoite	Complex K-Ca silicate	5-6
Chrysoberyl	Chrysoberyl	BeAl₂O₄	8.5
Chrysocolla	Chrysocolla	(Cu,Al)₂H₂Si₂O₅(OH)₄·nH₂O	2-4
Chrysoprase	Quartz	SiO₂	6.5-7
Citrine	Quartz	SiO₂	7
Clinohumite	Humite	(Mg,Fe)₉(SiO₄)₄(F,OH)₂	6
Coral	Organic	CaCO₃	3-4
Cordierite	Cordierite	(Mg,Fe)₂Al₄Si₅O₁₈	7-7.5
Crocoite	Crocoite	PbCrO₄	2.5-3
Cubic zirconia	Synthetic	ZrO₂	8-8.5
Cuprite	Cuprite	Cu₂O	3.5-4
Danburite	Danburite	CaB₂Si₂O₈	7-7.5
Demantoid	Garnet	Ca₃Fe₂(SiO₄)₃	6.5-7
Diamond	Diamond	C	10
Diaspore (Zultanite)	Diaspore	AlO(OH)	6.5-7
Diopside	Pyroxene	CaMgSi₂O₆	5.5-6.5
Dioptase	Dioptase	CuSiO₃·H₂O	5
Dumortierite	Dumortierite	Al₇(BO₃)(SiO₄)₃O₃	7-8.5
Emerald	Beryl	Be₃Al₂Si₆O₁₈	7.5-8
Enstatite	Pyroxene	MgSiO₃	5-6
Epidote	Epidote	Ca₂(Al,Fe)₃(SiO₄)(Si₂O₇)O(OH)	6-7
Euclase	Euclase	BeAlSiO₄(OH)	7.5
Eudialyte	Eudialyte	Na₄(Ca,Ce)₂(Fe,Mn)ZrSi₈O₂₂(OH,Cl)₂	5-5.5
Feldspar	Feldspar	(K,Na,Ca)(Al,Si)₄O₈	6-6.5
Fire agate	Quartz	SiO₂	6.5-7
Fluorite	Fluorite	CaF₂	4
Fuchsite	Mica	K(Al,Cr)₂(AlSi₃O₁₀)(OH)₂	2-3
Garnet	Garnet	(Ca,Fe,Mg,Mn)₃(Al,Fe,Cr)₂(SiO₄)₃	6.5-7.5
Gaspeite	Calcite	(Ni,Mg,Fe)CO₃	4.5-5
Glass	Man-made glass	SiO₂-based	5-6
Goshenite	Beryl	Be₃Al₂Si₆O₁₈	7.5-8
Grandidierite	Grandidierite	(Mg,Fe)Al₃(BO₃)(SiO₄)O₂	7.5
Grossular	Garnet	Ca₃Al₂(SiO₄)₃	6.5-7.5
Gypsum (selenite)	Gypsum	CaSO₄·2H₂O	2
Hackmanite	Sodalite	Na₈Al₆Si₆O₂₄(Cl₂,S)	5.5-6
Hambergite	Hambergite	Be₂BO₃(OH)	7.5
Hauyne	Sodalite	Na₃Ca(Si₃Al₃)O₁₂(SO₄)	5.5-6
Hawk's-eye	Quartz	SiO₂	7
Heliodor	Beryl	Be₃Al₂Si₆O₁₈	7.5-8
Hematite	Corundum	Fe₂O₃	5-6.5
Hessonite	Garnet	Ca₃Al₂(SiO₄)₃	6.5-7.5
Hiddenite	Pyroxene	LiAlSi₂O₆	6.5-7
Howlite	Howlite	Ca₂B₅SiO₉(OH)₅	3.5
Iolite	Cordierite	(Mg,Fe)₂Al₄Si₅O₁₈	7-7.5
Jadeite jade	Pyroxene	NaAlSi₂O₆	6.5-7
Jasper	Quartz	SiO₂	6.5-7
Jeremejevite	Jeremejevite	Al₆B₅O₁₅(F,OH)₃	6.5-7.5
Jet	Organic	Lignite (C, H, O)	2.5-4
Kornerupine	Kornerupine	(Mg,Fe)₄(Al,Fe)₆(SiO₄,BO₄)₅(O,OH)₂	6.5-7
Kunzite	Pyroxene	LiAlSi₂O₆	6.5-7
Kyanite	Kyanite	Al₂SiO₅	4.5-5 parallel; 6.5-7 across
Labradorite	Feldspar	(Ca,Na)(Al,Si)₄O₈	6-6.5
Lapis lazuli	Rock	Lazurite + calcite, pyrite	5-6
Larimar	Pectolite	NaCa₂Si₃O₈(OH)	5-6
Lazulite	Lazulite	MgAl₂(PO₄)₂(OH)₂	5.5-6
Lepidolite	Mica	K(Li,Al)₃(Si,Al)₄O₁₀(F,OH)₂	2.5-4
Malachite	Malachite	Cu₂CO₃(OH)₂	3.5-4
Maw-sit-sit	Rock	Kosmochlor + jadeite	6-7
Moissanite	Moissanite	SiC	9.25
Moldavite	Natural glass	SiO₂-rich	5-6
Moonstone	Feldspar	(K,Na)AlSi₃O₈	6-6.5
Morganite	Beryl	Be₃Al₂Si₆O₁₈	7.5-8
Musgravite	Taaffeite	BeMg₂Al₆O₁₂	8-8.5
Nephrite jade	Amphibole	Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂	6-6.5
Obsidian	Natural glass	SiO₂-rich	5-5.5
Onyx	Quartz	SiO₂	6.5-7
Opal	Opal	SiO₂·nH₂O	5-6.5
Orthoclase	Feldspar	KAlSi₃O₈	6
Painite	Painite	CaZrAl₉O₁₅(BO₃)	8
Pearl	Organic	CaCO₃ + conchiolin	2.5-3
Peridot	Olivine	(Mg,Fe)₂SiO₄	6.5-7
Petalite	Petalite	LiAlSi₄O₁₀	6-6.5
Pezzottaite	Beryl	CsBe₂LiAl₂Si₆O₁₈	8
Phenakite	Phenakite	Be₂SiO₄	7.5-8
Pollucite	Analcime	(Cs,Na)₂Al₂Si₄O₁₂·2H₂O	6.5-7
Poudretteite	Milarite	KNa₂B₃Si₁₂O₃₀	5
Prasiolite	Quartz	SiO₂	7
Prehnite	Prehnite	Ca₂Al(AlSi₃O₁₀)(OH)₂	6-6.5
Pyrite	Pyrite	FeS₂	6-6.5
Pyrope	Garnet	Mg₃Al₂(SiO₄)₃	7-7.5
Quartz	Quartz	SiO₂	7
Rhodochrosite	Calcite	MnCO₃	3.5-4
Rhodolite	Garnet	(Mg,Fe)₃Al₂(SiO₄)₃	7-7.5
Rhodonite	Pyroxenoid	(Mn,Fe,Mg,Ca)SiO₃	5.5-6.5
Rock crystal	Quartz	SiO₂	7
Rose quartz	Quartz	SiO₂	7
Ruby	Corundum	Al₂O₃	9
Sapphire	Corundum	Al₂O₃	9
Scapolite	Scapolite	(Na,Ca)₄(Al,Si)₁₂O₂₄(Cl,CO₃,SO₄)	5.5-6
Scheelite	Scheelite	CaWO₄	4.5-5
Serendibite	Sapphirine	Ca₂(Mg,Al)₆(Si,Al,B)₆O₂₀	6.5-7
Serpentine	Serpentine	Mg₃Si₂O₅(OH)₄	2.5-5.5
Sillimanite	Sillimanite	Al₂SiO₅	6.5-7.5
Sinhalite	Sinhalite	MgAlBO₄	6.5-7
Smithsonite	Calcite	ZnCO₃	4-4.5
Sodalite	Sodalite	Na₈Al₆Si₆O₂₄Cl₂	5.5-6
Spessartine	Garnet	Mn₃Al₂(SiO₄)₃	7-7.5
Sphalerite	Sphalerite	ZnS	3.5-4
Sphene (titanite)	Titanite	CaTiSiO₅	5-5.5
Spinel	Spinel	MgAl₂O₄	8
Spodumene	Pyroxene	LiAlSi₂O₆	6.5-7
Sugilite	Milarite	KNa₂(Fe,Mn,Al)₂Li₃Si₁₂O₃₀	5.5-6.5
Sunstone	Feldspar	(Ca,Na)(Al,Si)₄O₈	6-6.5
Taaffeite	Taaffeite	BeMg₃Al₈O₁₆	8-8.5
Tanzanite	Zoisite	Ca₂Al₃(SiO₄)(Si₂O₇)O(OH)	6-7
Tektite	Natural glass	SiO₂-rich	5.5-6.5
Tiger's-eye	Quartz	SiO₂	7
Topaz	Topaz	Al₂SiO₄(F,OH)₂	8
Tourmaline	Tourmaline	(Na,Ca)(Li,Mg,Fe,Al)₃Al₆(BO₃)₃Si₆O₁₈(OH,F)₄	7-7.5
Tsavorite	Garnet	Ca₃Al₂(SiO₄)₃	7-7.5
Turquoise	Turquoise	CuAl₆(PO₄)₄(OH)₈·4H₂O	5-6
Uvarovite	Garnet	Ca₃Cr₂(SiO₄)₃	6.5-7
Variscite	Variscite	AlPO₄·2H₂O	3.5-4.5
Vesuvianite (idocrase)	Vesuvianite	Ca₁₀(Mg,Fe)₂Al₄(SiO₄)₅(Si₂O₇)₂(OH)₄	6-7
Vivianite	Vivianite	Fe₃(PO₄)₂·8H₂O	1.5-2
Wavellite	Wavellite	Al₃(PO₄)₂(OH,F)₃·5H₂O	3.5-4
Zircon	Zircon	ZrSiO₄	6-7.5
Zoisite	Epidote	Ca₂Al₃(SiO₄)(Si₂O₇)O(OH)	6-7

A note on the numbers

Mohs hardness is an ordinal scale, so the numerical steps are not equal. The distance from corundum at 9 to diamond at 10 is far greater than the distance from talc at 1 to gypsum at 2, even though both look like a single step. Values can also vary with composition, crystallographic direction, weathering, and whether the material is an aggregate, a rock, a composite, or a treated product.

Hardness is also only one of three properties that decide how a stone survives daily wear, alongside toughness and stability. All three are explained in Hardness of Crystals and Gemstones.

If you are choosing a stone with wear in mind, our untreated gemstones and the harder species such as sapphire, spinel, topaz, and quartz are good places to start.

Frequently asked questions

What is the hardest gemstone after diamond?

Among natural gemstones in common use, ruby and sapphire, the two colour varieties of corundum, at 9 on the Mohs scale.

Which gemstones are best for everyday rings?

Stones at 7 or above, such as sapphire, ruby, spinel, topaz and quartz. They resist the fine quartz dust in everyday grime, which slowly dulls softer stones.

Is hardness the same as durability?

No. Hardness is resistance to scratching. Durability also depends on toughness and cleavage: topaz is 8 on the Mohs scale but can still split along its perfect cleavage after a sharp knock.

About the author

Svetozar Simov

Hi, I'm Svetozar, the owner and founder of Lapis Magica.

For more than 15 years, I've been captivated by the magic of gemstones and crystals.

On the blog, I share what I've learned about gemstones, treatments, and everything in between.

Think of me as your friendly neighborhood gemstone guide, always happy to share what I know and help you explore the remarkable variety of materials created by nature.

Written by Lapis Magica. If you spot an error or have a question about this article, write to contact@lapismagica.com.

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