Understanding Gemstone Hardness – The Mohs Scale and Jewelry Durability

What Is Gemstone Hardness?

When selecting a gemstone, one of the most important—but often overlooked—factors is hardness. Hardness determines how well a gem can resist surface scratches, which directly affects its durability, wearability, and long-term appearance.

In gemology, hardness refers specifically to scratch resistance—how easily a stone’s surface can be marked by another material. This is not the same as:

• Toughness – the gem’s ability to resist breaking, chipping, or cracking
• Stability – resistance to heat, chemicals, and environmental changes

A gem can be extremely hard but still fragile if it has low toughness (e.g., emeralds).

The Mohs Hardness Scale

Gemologists use the Mohs scale to measure hardness—a relative ranking system developed by German mineralogist Friedrich Mohs in 1822. The scale ranges from:

• 1 (talc) – softest
• to 10 (diamond) – hardest natural substance

In practical terms:

• A gem can scratch any material below it on the scale
• It can be scratched by anything above it

Example: Quartz (Mohs 7) can scratch fluorite (Mohs 4), but it will be scratched by topaz (Mohs 8).

⚠️ Important: The Mohs scale is not linear. While diamond (10) is just one number above corundum (9 – rubies and sapphires), it is many times harder. That’s why diamond remains the most scratch-resistant gemstone used in jewelry.

Why Does Hardness Matter?

Gemstone hardness directly affects its ability to resist daily wear and surface damage. Common airborne dust contains quartz (hardness 7). This means:

• Any gemstone with hardness below 7 can become scratched and dull over time
• This is especially relevant for rings or bracelets, which face more friction

Soft gemstones such as opal, apatite, or fluorite require extra care:

• Store separately from other gems
• Remove before sports, cleaning, or manual work
• Re-polish occasionally to restore luster

What Gemstone Hardness Is Suitable for Jewelry?

• Soft stones (Mohs 1–2): Not suitable for regular wear
• Medium-hard stones (Mohs 3–5): Best for occasional wear or protected settings (e.g., earrings, pendants)
• Hard stones (Mohs 6+): Ideal for daily wear, including rings and engagement rings

Most popular gemstones fall between Mohs 6 and 8, offering a balance of beauty, rarity, and practical durability.

Hardness Classification of Sosna Gems Gemstones

Softer stones – for occasional wear

Apatite, Opal, Sphalerite, Sphene

Medium hardness – can be worn daily with care

Kunzite, Spodumene, Tanzanite, Zircon

Standard hardness – suitable for regular wear

Amethyst, Citrine, Ametrine, Smoky Quartz, Tourmaline, Garnet, Peridot, Morganite, Beryl

High hardness – ideal for everyday wear

Aquamarine, Spinel, Alexandrite, Topaz, Imperial Topaz, Emerald (requires gentle handling), Ruby, Sapphire

This classification helps you select gemstones best suited to your lifestyle and usage. For softer or fragile gems, choose protective settings. For daily-wear jewelry, opt for higher hardness with proven durability.

An Expert Resource

Below this article, you’ll find a comprehensive Mohs scale table with the hardness of over 150 natural gemstone varieties. It’s one of the most complete references online, including rare and collector stones.

Whether you're creating a custom ring, choosing a birthstone, or buying a gift, understanding hardness will help you make informed and lasting decisions.

	Diamond	10
	Ruby	9
	Star Ruby	9
	Sapphire	9
	Star Sapphire	9
	Alexandrite	8.5
	Alexandrite Cat's Eye	8.5
	Chrysoberyl	8.5
	Chrysoberyl Cat's Eye	8.5
	Vanadium Chrysoberyl	8.5
	Taaffeite	8-8.5
	Spinel	8
	Topaz	8
	Imperial Topaz	8
	Pezzotaite	8
	Emerald	7.5-8
	Enstatite	7.5-8
	Aquamarine	7.5-8
	Morganite	7.5-8
	Goshenite Beryl	7.5-8
	Golden Beryl	7.5-8
	Painite	7.5-8
	Phenakite	7.5-8
	Red Beryl (Bixbite)	7.5-8
	Andalusite	7.5
	Euclase	7.5
	Grandidierite	7.5
	Hambergite	7.5
	Dumortierite	7-8.5
	Almandine Garnet	7-7.5
	Danburite	7-7.5
	Iolite	7-7.5
	Pyrope Garnet	7-7.5
	Spessartite Garnet	7-7.5
	Rhodolite Garnet	7-7.5
	Color-Change Garnet	7-7.5
	Chrome Tourmaline	7-7.5
	Malaia Garnet	7-7.5
	Paraiba Tourmaline	7-7.5
	Rubellite Tourmaline	7-7.5
	Tourmaline	7-7.5
	Uvarovite Garnet	7-7.5
	Amethyst	7
	Aventurine	7
	Ametrine	7
	Citrine	7
	Gem Silica	7
	Kornerupine	7
	Rock Crystal	7
	Rose Quartz	7
	Smoky Quartz	7
	Jeremejevite	6.5-7.5
	Sillimanite	6.5-7.5
	Zircon	6.5-7.5
	Agate	6.5-7
	Axinite	6.5-7
	Bloodstone	6.5-7
	Carnelian	6.5-7
	Chalcedony	6.5-7
	Chrome Chalcedony	6.5-7
	Chrysoprase	6.5-7
	Demantoid Garnet	6.5-7
	Diaspore	6.5-7
	Grossular Garnet	6.5-7
	Hessonite Garnet	6.5-7
	Hiddenite	6.5-7
	Jadeite Jade	6.5-7
	Jasper	6.5-7
	Mali Garnet	6.5-7
	Kunzite	6.5-7
	Leuco Garnet	6.5-7
	Onyx	6.5-7
	Peridot	6.5-7
	Serendibite	6.5-7
	Sinhalite	6.5-7
	Spodumene	6.5-7
	Tanzanite	6.5-7
	Tsavorite Garnet	6.5-7
	Idocrase (Vesuvianite)	6.5
	Cassiterite	6-7
	Epidote	6-7
	Maw-Sit-Sit	6-7
	Unakite	6-7
	Amazonite	6-6.5
	Andesine	6-6.5
	Oligoclase	6-6.5
	Benitoite	6-6.5
	Labradorite	6-6.5
	Moonstone	6-6.5
	Nephrite Jade	6-6.5
	Orthoclase	6-6.5
	Petalite	6-6.5
	Prehnite	6-6.5
	Scheelite	6-6.5
	Sugilite	6-6.5
	Sunstone	6-6.5
	Zoisite	6-6.5
	Amblygonite	6
	Clinohumite	6
	Hematite	5.5-6.5
	Mexican Fire Opal	5.5-6.5
	Opal	5.5-6.5
	Rhodonite	5.5-6.5
	Actinolite	5.5-6
	Azurite	5.5-6
	Hackmanite	5.5-6
	Hauyne	5.5-6
	Scapolite	5.5-6
	Sodalite	5.5-6
	Moldavite	5.5
	Diopside	5-6
	Chrome Diopside	5-6
	Lapis Lazuli	5-6
	Poudretteite	5-6
	Turquoise	5-6
	Brazilianite	5.5
	Datolite	5-5.5
	Eudialyte	5-5.5
	Obsidian	5-5.5
	Sphene (Titanite)	5-5.5
	Apatite	5
	Cat's Eye Apatite	5
	Dioptase	5
	Hemimorphite	5
	Smithsonite	5
	Charoite	4.5-5
	Gaspeite	4.5-5
	Larimar	4.5-5
	Kyanite	4-7
	Bastnasite	4-5
	Carletonite	4-4.5
	Ammolite (Korite)	4
	Fluorite	4
	Rhodochrosite	4
	Williamsite	4
	Aragonite	3.5-4
	Azurite	3.5-4
	Cuprite	3.5-4
	Malachite	3.5-4
	Sphalerite	3.5-4
	Coral	3-4
	Barite	3-3.5
	Celestine	3-3.5
	Cerussite	3-3.5
	Howlite	3-3.5
	Calcite	3
	Cobaltocalcite	3
	Pearl	2.5-4.5
	Jet	2.5-4
	Lepidolite	2.5-3
	Chrysocolla	2-4
	Amber	2-2.5
	Cinnabar	2-2.5
	Ulexite	2-2.5