Gemstone profile and identification guide
Kyanite
Kyanite is an aluminum silicate mineral notable for pronounced hardness anisotropy and blue pleochroic colour.
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Overview
Kyanite is an aluminum silicate mineral notable for pronounced hardness anisotropy and blue pleochroic colour.
Did you know? Kyanite can show different hardness values depending on crystallographic direction.
Use this profile as a collector reference and educational guide for quick on-page comparison, then validate with the interactive identification system.
Identification
Name: Kyanite
Scientific classification: Silicate (Kyanite)
Hardness: 6 Mohs
Transparency: transparent
Lustre: vitreous
Crystal system: Triclinic
Primary colour: Blue
Secondary colour: Blue Green
Colour family: Blues
Hardness anisotropy and pleochroism are key clues, confirmed by triclinic crystal habit and optical testing.
Verification Status
Status: verified-core-fields
Reference priority: GIA, Gem-A, Mindat, International Gem Society
Core identity, locality, and physical-property fields reviewed against standard gemological references.
Values are given as practical gemological ranges where appropriate.
Physical Properties
Hardness category: hard
Hardness value: 6 Mohs
Chemical composition: Aluminum silicate [Al2SiO5]
Crystal system: Triclinic
Common locations: Nepal, India, Brazil, Myanmar, Tanzania
Learn more: Gem-A gemstone education resources.
Colour Variations
Typically blue, sometimes blue-green or near-colorless, often with directional hardness differences.
Optical effects: Pleochroism
Detailed Gemology
Mineral species: Kyanite
Mineral group: Nesosilicate group
Chemical formula: Aluminum silicate [Al2SiO5]
Mohs hardness: 6
Crystal system: Triclinic
Lustre: vitreous
Transparency: transparent
Streak: White
Cleavage: Perfect in one direction
Fracture: Uneven to splintery
Specific gravity: 3.53-3.67
Refractive index: 1.712-1.734
Optical phenomena: Pleochroism
Colour range: Blue, blue-green, colorless, grey
Common inclusions: Fibrous zones, liquid inclusions, rutile needles
Geological environment: Regional metamorphic schists and gneisses
Principal mining regions: Nepal, India, Brazil, Myanmar, Tanzania
Important commercial sources: Gem kyanite is supplied from Nepal, India, and Brazil, with additional East African production
Historical significance: Primarily a collector and niche jewellery stone with increased market visibility in recent decades.
Common treatments: Generally untreated.
Synthetic or imitation forms: Glass and synthetic blue gemstones may be used as imitations.
Common look-alikes: Blue sapphire, iolite, blue spinel
Jewellery uses: Kyanite is used chiefly for Pendants and earrings or protected ring settings due to cleavage.. In the trade it is commonly fashioned as faceted stones, calibrated cuts, and higher-clarity collector pieces, with Mohs hardness 6 guiding suitable jewellery applications.
Care recommendations: Brittle with perfect cleavage; use protective settings and avoid impact, ultrasonic, and steam cleaning.
Cross-check profile data with GIA Gem Encyclopedia and Mindat entry for Kyanite.
Formation
Forms in medium- to high-pressure metamorphic rocks such as schists and gneisses.
Origin
Gem kyanite is supplied from Nepal, India, and Brazil, with additional East African production
Uses
Best for: Kyanite is used chiefly for Pendants and earrings or protected ring settings due to cleavage.. In the trade it is commonly fashioned as faceted stones, calibrated cuts, and higher-clarity collector pieces, with Mohs hardness 6 guiding suitable jewellery applications.
Ideal uses: Pendants and earrings or protected ring settings due to cleavage.
Care
Brittle with perfect cleavage; use protective settings and avoid impact, ultrasonic, and steam cleaning.
Need another candidate? Use advanced gemstone search or return to the identification guide.
Related gemstones by colour
Related gemstones by hardness
Commonly confused gemstones
Kyanite FAQ
How can I identify Kyanite?
Compare hardness (6 Mohs), crystal system (Triclinic), colour profile, and lustre (vitreous) with your sample. Then cross-check related gemstones listed above.
What colour range does Kyanite appear in?
Typically blue, sometimes blue-green or near-colorless, often with directional hardness differences.
Where is Kyanite commonly used?
Pendants and earrings or protected ring settings due to cleavage.. For maintenance, follow the care guidance in this profile.
Scientific References
GIA: general gemstone identity (reviewed) - Batch 01 factual verification pass.
Gem-A: gemological terminology and testing references (reviewed) - Batch 01 factual verification pass.
Mindat: mineral species and principal localities (reviewed) - Batch 01 factual verification pass.
International Gem Society: gem trade context and treatment overview (reviewed) - Batch 01 factual verification pass.