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Streaky blue, also green, black, orange

Kyanite crystals

Kyanite is aluminum silicate (Al₂SiO₅), streaky blue, also green, black, orange, rated 4.5–7 (varies by direction) on the Mohs scale. Traditionally, it is linked to clear expression and cutting through confusion — attributed, not demonstrated.

Mohs hardness
4.5–7 (varies by direction) about as hard as window glass
Crystal system
Triclinic Al₂SiO₅
Main sources today
Nepal also Brazil, India

Stones described in similar terms: diamond, topaz, selenite, garnet, zircon, jade, fluorite and labradorite.

Linked in crystal practice with the throat chakra and third eye chakra.

Further along the same lines: sapphire, peridot and turquoise.

Kyanite Crystals: Meaning, Hardness and Origins

Properties

Composition Aluminum silicate (Al₂SiO₅)
Hardness (Mohs) 4.5–7 (varies by direction)
Crystal system Triclinic
Color Streaky blue, also green, black, orange
Mined in Nepal, Brazil, India, Kenya, USA

Worth knowing

One of the few minerals with two hardness values: about 4.5 along the crystal and up to 7 across it. Cutting it requires knowing which way you are working.

History

Named from the Greek kyanos, "dark blue".

Buying

Buying Kyanite: fakes, value and treatments

What it is confused with

Blue sapphire in faceted stones. Kyanite's long blade-shaped crystals are distinctive in rough form.

What decides the price

Inexpensive in bladed form; clean, evenly blue faceted stones from Nepal are the rare gem grade.

Where it is used

Heat-resistant ceramics, including the porcelain in spark plugs.

A less familiar fact

Kyanite is scratched by a knife along its length but not across it, and geologists use it as a sign of high pressure in metamorphic rock.

Practical

Caring for Kyanite

How to clean it

Soft brush and soapy water. No ultrasonic — kyanite has perfect cleavage in two directions.

How to tell it is real

Distinctive enough to be rarely faked. The two-directional hardness is the test: it scratches easily along the crystal and resists across it.

How to store stones so they do not scratch each other →

How hard is Kyanite?

Kyanite’s range is the widest here because its hardness changes with direction — about 4.5 along the length of a blade, about 7 across it — and perfect cleavage makes it fragile in a ring. Only Sodalite shares its place on our scale. Among the stones in this reference, the next softer is Turquoise (5–6) and the next harder Opal (5.5–6.5).

Kyanite on the Mohs hardness scale
Kyanite on the Mohs hardness scaleMohs scale from talc (1) to diamond (10), with the 43 stones of our reference as dots and Kyanite (4.5–7 (varies by direction)) marked as a bar.Kyanite: Mohs 4.5–7Kyanite 4.5–7Garnet: Mohs 6.5–7.5Amethyst: Mohs 7Citrine: Mohs 7Rose Quartz: Mohs 7Clear Quartz: Mohs 7Smoky Quartz: Mohs 7Aquamarine: Mohs 7.5–8Emerald: Mohs 7.5–8Bloodstone: Mohs 6.5–7Peridot: Mohs 6.5–7Sardonyx: Mohs 6.5–7Zircon: Mohs 6–7.5Carnelian: Mohs 6.5–7Onyx: Mohs 6.5–7Agate: Mohs 6.5–7Tiger's Eye: Mohs 6.5–7Aventurine: Mohs 6.5–7Diamond: Mohs 10Pearl: Mohs 2.5–4.5Alexandrite: Mohs 8.5Moonstone: Mohs 6–6.5Labradorite: Mohs 6–6.5Pyrite: Mohs 6–6.5Ruby: Mohs 9Sapphire: Mohs 9Spinel: Mohs 8Topaz: Mohs 8Opal: Mohs 5.5–6.5Rhodonite: Mohs 5.5–6.5Tourmaline: Mohs 7–7.5Turquoise: Mohs 5–6Lapis Lazuli: Mohs 5–6Hematite: Mohs 5–6Tanzanite: Mohs 6–7Jade: Mohs 6–7Obsidian: Mohs 5–5.5Malachite: Mohs 3.5–4Amber: Mohs 2–2.5Selenite: Mohs 2Fluorite: Mohs 4Sodalite: Mohs 5.5–6Kyanite: Mohs 4.5–7Lepidolite: Mohs 2.5–31Talc2Gypsum3Calcite4Fluorite5Apatite6Orthoclase7Quartz8Topaz9Corundum10Diamondfingernail 2.5window glass 5.5household dust (quartz) 7Source: Mohs scale minerals · ranges from our 43-stone referenceastrohot.com
Kyanite on the Mohs hardness scaleMohs scale from talc (1) to diamond (10), with the 43 stones of our reference as dots and Kyanite (4.5–7 (varies by direction)) marked as a bar.Kyanite: Mohs 4.5–7Kyanite 4.5–71Talc2Gypsum3Calcite4Fluorite5Apatite6Orthoclase7Quartz8Topaz9Corundum10Diamondfingernail 2.5glass 5.5dust 7Source: Mohs scale minerals · ranges from our 43-stone referenceastrohot.com

Kyanite, at 4.5–7, is harder than 10 of the other 42 stones here and softer than 31.

Traditional associations

Kyanite is traditionally linked to clear expression and cutting through confusion. Chakra in crystal practice: Throat, Third Eye. Element: Air.

What is measured here and what is tradition →

Questions about Kyanite

What is Kyanite made of?

Aluminum silicate (Al₂SiO₅), crystallizing in the triclinic system.

Where does Kyanite come from?

Nepal, Brazil, India, Kenya, USA.

Can Kyanite be worn every day?

Not in a ring. At 4.5–7 (varies by direction) on the Mohs scale it is better kept for pendants, earrings or display, away from knocks, because of its perfect cleavage.

← All gemstones

Cite this page

AstroHot. “Kyanite Crystals: Meaning, Hardness and Origins.” Accessed October 28, 2026. https://astrohot.com/crystals/gemstones/kyanite/

For Wikipedia {{cite web |title=Kyanite Crystals: Meaning, Hardness and Origins |url=https://astrohot.com/crystals/gemstones/kyanite/ |website=AstroHot |access-date=2026-10-28}}