Mohs Hardness of Common Gemstones

The Mohs hardness scale measures how resistant a mineral or gemstone is to scratching.

The scale runs from 1 to 10, with talc at 1 and diamond at 10.

One important point: the Mohs scale is relative, not linear. A gemstone rated 10 is not simply “one point harder” than a gemstone rated 9. GIA explains that diamond is many times harder than corundum even though diamond is rated 10 and ruby and sapphire are rated 9.

For jewelry shoppers, this makes Mohs hardness one of the easiest ways to compare how well a gemstone resists everyday scratching.

Complete Gemstone Mohs Hardness Chart

The following chart is based on the gemstone names in the Willwork Jewelry rough-stone inventory updated August 15, 2026.

Gemstone	Mohs Hardness
Natural Diamond	10
Natural Salt & Pepper Diamond	10
Lab Grown Diamond	10
White Moissanite	9.25
Blue Moissanite	9.25
Green Moissanite	9.25
Gray Moissanite	9.25
Black Moissanite	9.25
Lab Created Sapphire	9
Natural Blue Sapphire	9
Lab Created Pink Sapphire	9
Lab Created Yellow Sapphire	9
Lab Created White Sapphire	9
Lab Created Purple Sapphire	9
Lab Created Cornflower Blue Sapphire	9
Natural Green Sapphire	9
Lab Grown Green Sapphire	9
Lab Created Green Sapphire	9
Lab Created Padparadscha Pink Sapphire	9
Natural Ruby	9
Lab Created Ruby	9
Lab Created Blue Star Sapphire	9
Natural Black Star Sapphire	9
Lab Created Alexandrite	8.5
Natural London Blue Topaz	8
Natural Sky Blue Topaz	8
Natural Swiss Blue Topaz	8
Natural White Topaz	8
Lab Created Mystic Topaz	8
Natural Black Spinel	8
Lab Created Emerald	7.5–8
Natural Emerald	7.5–8
Natural Aquamarine	7.5–8
Natural Pink Morganite	7.5–8
Natural Peach Morganite	7.5–8
Lab Created Morganite	7.5–8
Natural Pink Tourmaline	7–7.5
Natural Green Tourmaline	7–7.5
Natural Gray Tourmaline	7–7.5
Lab Created Paraiba	7–7.5
Natural Red Garnet	6.5–7.5
Lab Created Green Garnet	6.5–7.5
Lab Created Spessartite Garnet	6.5–7.5
Natural Tsavorite Garnet	6.5–7.5
Natural Amethyst	7
Natural Lavender Amethyst	7
Natural Green Amethyst	7
Natural Ametrine	7
Natural Black Rutilated Quartz	7
Natural Green Rutilated Quartz	7
Natural Citrine	7
Natural Rose Quartz	7
Natural Smoky Quartz	7
Natural Black Onyx	6.5–7
Natural Bloodstone	6.5–7
Natural Aventurine	6.5–7
Natural Moss Agate	6.5–7
Natural Peridot	6.5–7
Natural Sunstone	6–7
Natural Tanzanite	6–7
Natural Moonstone	6–6.5
Natural Black Star Diopside	5.5–6.5
Lab Created White Opal	5.5–6.5
Lab Created Black Opal	5.5–6.5
Lab Created Blue Opal	5.5–6.5
Lab Created Purple Opal	5.5–6.5
Lab Created Green Opal	5.5–6.5
Lab Created Blue Sandstone	Approx. 5.5–6.5
Lab Created Green Sandstone	Approx. 5.5–6.5
Natural Turquoise	5–6
Natural Lapis Lazuli	5–5.5
Natural Freshwater Pearl	2.5–4.5
Natural Saltwater Pearl	2.5–4.5

Note: Mohs hardness values are approximate. Gemstone hardness can vary within a mineral species, and lab-created materials may vary according to their exact composition. Hardness measures scratch resistance, not overall toughness or resistance to breaking.

A Few Important Notes About Gemstone Hardness

The numbers above should be read as reference values for the underlying gemstone material, not as a guarantee for every commercial product sold under a trade name.

This matters because some inventory names describe a mineral, while others describe a color, treatment, manufacturing method or commercial name.

For example:

• Sapphire is corundum and has a Mohs hardness of 9.
• Ruby is also corundum and has a Mohs hardness of 9.
• Emerald is beryl and has a Mohs hardness of 7.5–8.
• Aquamarine is beryl and has a Mohs hardness of 7.5–8.
• Morganite is beryl and has a Mohs hardness of 7.5–8.
• Amethyst, citrine, smoky quartz and rose quartz are quartz varieties and are approximately Mohs 7.
• Different colors of the same mineral generally do not change the mineral's Mohs hardness.

GIA's Gem Encyclopedia gives emerald at 7.5–8, aquamarine at 7.5–8, morganite at 7.5–8, tanzanite at 6–7 and opal at 5–6.5.

Natural vs. Lab Created: Does Lab Created Mean Softer?

Not necessarily.

A lab created gemstone can have essentially the same chemical, physical and optical properties as its natural counterpart when it is a true lab created version of the same material.

For example:

• Lab created sapphire: approximately 9
• Lab created ruby: approximately 9
• Lab created emerald: approximately 7.5–8
• Lab created alexandrite: approximately 8.5
• Lab-grown diamond: 10

However, lab created does not mean imitation.

A glass imitation of sapphire, for example, does not have the same hardness as lab created sapphire.

This is why a commercial name alone should not always be used to assign a Mohs number.

What About CZ?

Cubic zirconia (CZ) has a Mohs hardness of approximately 8–8.5.

GIA reports CZ at 8.5 in its gem-imitation reference materials.

This makes CZ considerably harder than quartz and many softer ornamental stones, although it is still below sapphire, moissanite and diamond.

What About Herkimer Diamond?

One inventory name requires special clarification:

“Herkimer Diamond” should not be confused with diamond.

When this trade name refers to Herkimer Diamond, it is actually a naturally occurring quartz crystal, not diamond.

Quartz has a Mohs hardness of approximately 7.

Therefore:

Herkimer Diamond = approximately Mohs 7, if it is genuine quartz.

The word “diamond” in the commercial name describes its appearance, not its mineral identity.

What About Lapis Lazuli?

Lapis lazuli is particularly interesting because it is a rock made of multiple minerals, rather than one single mineral species.

GIA gives lapis lazuli a hardness of approximately 5–6, depending on its mineral composition.

This is why assigning one exact hardness number to every piece of lapis would be misleading.

What About Turquoise?

Turquoise has a Mohs hardness of approximately 5–6.

GIA confirms this range and notes that turquoise can also be treated to improve appearance or durability.

Willwork Jewelry's inventory contains several turquoise descriptions, including matrix turquoise, and matrix-free turquoise.

What About Pearl?

Pearl is much softer than most crystalline gemstones.

A commonly used range is approximately:

Mohs 2.5–4.5

GIA educational material gives natural/cultured pearl hardness around the lower part of this range, which is why pearl jewelry requires considerably more care than diamond, sapphire or moissanite.

Pearls should also be stored separately from harder gemstones because harder materials can scratch their nacre surface.

Mohs Hardness Is Not the Same as Durability

A gemstone's Mohs hardness tells you about scratch resistance.

It does not tell the whole story about whether a gemstone will survive an impact.

GIA divides gemstone durability into three major considerations:

1. Hardness — resistance to scratching and abrasion
2. Toughness — resistance to breaking, chipping and fracturing
3. Stability — resistance to heat, light, chemicals and environmental changes

For example, tanzanite has a hardness of 6–7 but also has cleavage and fair-to-poor toughness, so it needs more protection from hard impacts.

Emerald has a hardness of 7.5–8 but also requires more care than ruby or sapphire because of its typical inclusions and fractures.

Tourmaline measures 7–7.5, while garnet ranges from 6.5–7.5.

Which Gemstones Are Best for Everyday Jewelry?

As a simple rule of thumb:

Very high scratch resistance

• Diamond — 10
• Moissanite — 9.25
• Sapphire — 9
• Ruby — 9

High hardness

• Alexandrite — 8.5
• Spinel — 8
• Topaz — 8

Good hardness

• Emerald — 7.5–8
• Aquamarine — 7.5–8
• Morganite — 7.5–8
• Tourmaline — 7–7.5
• Quartz varieties — 7
• Garnet — 6.5–7.5

Softer gemstones requiring more care

• Tanzanite — 6–7
• Moonstone — 6–6.5
• Labradorite — 6–6.5
• Opal — 5–6.5
• Turquoise — 5–6
• Lapis Lazuli — 5–6
• Pearl — 2.5–4.5

The right gemstone depends on both its hardness and how you plan to wear it.

Shop Gemstone Jewelry by Stone Type

Willwork Jewelry currently organizes its jewelry collection by gemstone, including Alexandrite, Emerald, Moissanite, Opal, Amethyst, Aquamarine, Citrine, Lab-Grown Diamond, Garnet, Labradorite, Moonstone, Morganite, Peridot, Pearl, Ruby, Rose Quartz, Sapphire, Sunstone, Tanzanite, Tourmaline, Topaz, Turquoise, Lapis Lazuli, Padparadscha, Paraiba and Diamond.

Explore the complete Willwork Jewelry Shop by Gemstone Collection.

For some of the most popular gemstone categories:

Moissanite Jewelry — Mohs 9.25

Emerald Jewelry — Mohs 7.5–8

Tanzanite Jewelry — Mohs 6–7

Final Note

Mohs hardness is a useful way to compare scratch resistance, but it should not be treated as a complete measure of gemstone durability.

For a jewelry buyer, the best question is not simply:

“Which gemstone has the highest Mohs hardness?”

It is:

“Which gemstone has the right hardness, toughness, stability and design for the way I will wear it?”

For Willwork Jewelry customers, the chart mentioned above provides a quick starting point for comparing the gemstones available across our collections and choosing a stone that matches both personal style and everyday lifestyle

Want to know which gemstones are best suited for rings, necklaces, and earrings? Click here to learn more:  Is Your Favorite Gemstone Durable Enough For Everyday Wear? Understanding Mohs Hardness Before Buying Jewelry