Guide Gemstone Hardness

In gemology, gem hardness is measured on a scale known as the Mohs scale, which assigns minerals a value between 1 (softest) and 10 (hardest). This scale was devised by a German mineralogist, Frederick Mohs, in 1822. It defines hardness in terms of scratch resistance, where a harder mineral will scratch a softer one, but not vice versa. 

Gems with a hardness rating of 1-2 are considered soft, while those in the range of 3-5 are medium hard. Gems over 6 are considered hard and thus suitable for jewelry.

The polish of gems with a Mohs hardness of less than 7 can be damaged by common dust, which contains tiny particles of quartz (hardness 7). Thus softer stones need to be worn and stored carefully, and repolished from time to time to maintain their luster.

This illustrated chart shows hardness ratings for 155 natural gemstone varieties. It is the most complete and accurate hardness scale for gemstones available online, and includes many rare varieties.

	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