Gemstone reference

43 stones with composition, hardness, crystal system and origin — plus what each is traditionally used for.

Stone Colour Mohs System Chakra
Agate Banded, in almost any colour 6.5–7 Trigonal Varies by variety
Alexandrite Green in daylight, red under incandescent light 8.5 Orthorhombic Heart, Crown
Amber Golden yellow to deep orange-brown 2–2.5 Amorphous Solar Plexus, Sacral
Amethyst Pale lilac to deep purple 7 Trigonal Third Eye, Crown
Aquamarine Pale blue to blue-green 7.5–8 Hexagonal Throat
Aventurine Green, also blue, peach, grey 6.5–7 Trigonal Heart
Bloodstone Dark green with red spots 6.5–7 Trigonal Root, Heart
Carnelian Orange to reddish brown 6.5–7 Trigonal Sacral
Citrine Pale yellow to amber brown 7 Trigonal Solar Plexus
Clear Quartz Colourless, transparent 7 Trigonal All, particularly Crown
Diamond Colourless, also yellow, brown, blue, pink 10 Cubic Crown
Emerald Green to bluish green 7.5–8 Hexagonal Heart
Fluorite Purple, green, blue, yellow, often banded 4 Cubic Third Eye, Heart
Garnet Deep red to orange, green, purple 6.5–7.5 Cubic Root
Hematite Metallic silver-grey to black 5–6 Trigonal Root
Jade Green, also white, lavender, black 6–7 Monoclinic Heart
Kyanite Streaky blue, also green, black, orange 4.5–7 (varies by direction) Triclinic Throat, Third Eye
Labradorite Grey with blue, green and gold flashes 6–6.5 Triclinic Third Eye, Throat
Lapis Lazuli Deep blue with gold pyrite flecks 5–6 Cubic (lazurite) Third Eye, Throat
Lepidolite Lilac to pinkish purple, often micaceous and flaky 2.5–3 Monoclinic Third Eye, Crown
Malachite Banded bright and dark green 3.5–4 Monoclinic Heart, Solar Plexus
Moonstone White to grey with blue sheen 6–6.5 Monoclinic Sacral, Third Eye
Obsidian Black, sometimes with sheen or snowflake patterning 5–5.5 Amorphous Root
Onyx Black, or black banded with white 6.5–7 Trigonal Root
Opal White, black or transparent with spectral flashes 5.5–6.5 Amorphous Crown, Heart
Pearl White, cream, pink, grey, black 2.5–4.5 Orthorhombic (aragonite) Sacral, Crown
Peridot Yellow-green to olive 6.5–7 Orthorhombic Heart, Solar Plexus
Pyrite Brassy metallic yellow 6–6.5 Cubic Solar Plexus
Rhodonite Rose pink with black manganese veining 5.5–6.5 Triclinic Heart
Rose Quartz Pale pink to rosy 7 Trigonal Heart
Ruby Red to purplish red 9 Trigonal Root, Heart
Sapphire Blue, also pink, yellow, green, colourless 9 Trigonal Throat, Third Eye
Sardonyx Banded reddish brown and white 6.5–7 Trigonal Root
Selenite Translucent white to colourless 2 Monoclinic Crown
Smoky Quartz Pale grey-brown to near black 7 Trigonal Root
Sodalite Royal blue with white veining 5.5–6 Cubic Third Eye, Throat
Spinel Red, pink, blue, purple, black 8 Cubic Root, Heart
Tanzanite Violet blue to deep purple 6–7 Orthorhombic Third Eye, Crown
Tiger's Eye Golden brown with a shifting band of light 6.5–7 Trigonal Solar Plexus, Root
Topaz Colourless, blue, yellow, imperial orange-pink 8 Orthorhombic Solar Plexus, Throat
Tourmaline Every colour; often several in one crystal 7–7.5 Trigonal Varies by colour — black for Root, pink for Heart
Turquoise Sky blue to green, often with dark matrix veining 5–6 Triclinic Throat
Zircon Blue, golden, red, green, colourless 6–7.5 Tetragonal Root, Crown

How to read the Mohs scale

Mohs hardness measures scratch resistance, not toughness. It runs from talc at 1 to diamond at 10, and the steps are not even — diamond is roughly four times harder than corundum at 9, which is itself twice as hard as topaz at 8.

The number that matters most in practice is 7. Airborne dust is largely quartz, which sits at 7, so anything softer will gradually dull from nothing more than being in a room. That single fact explains why opal rings cloud over and sapphire rings do not.

Hardness also says nothing about breaking. Diamond tops the scale and will still split cleanly if struck along a cleavage plane, while jade — much softer — is among the hardest stones to break because its fibres interlock.