Blue Kyanite
Kyanite (IMA approved name: Kyanite) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Triclinic; typically forms in long, bladed crystals that can be fibrous or radiating. The specimens shown are polished tumble/cabochon forms.
Mineral Group
Silicate; Subgroup: Nesosilicate (orthosilicate)
Chemical Formula
Al2SiO5 (Aluminum Silicate)
Formation Process
Metamorphic; typically forms during regional metamorphism of clay-rich sediments at high pressures. It is an aluminosilicate polymorph with andalusite and sillimanite.
About This Crystal
Exhibits a deep to dusty blue color with white or gray streaking and a distinct fibrous or bladed internal texture. Polished surfaces show a vitreous to pearly luster. These specific stones are opaque to translucent with characteristic uneven color zoning.
Physical Characteristics
Color: Blue with white/gray streaks; Streak: White; Cleavage: Perfect {100} and good {010}; Fracture: Splintery; Specific Gravity: 3.53–3.67; Fluorescence: Weak red under UV; Piezoelectricity: Not characteristic.
Optical Properties
Refractive Index: 1.712–1.734; Birefringence: 0.015–0.017; Pleochroism: Strongly trichroic (colorless, violet-blue, cobalt-blue). It is biaxial negative.
Hardness & Durability
Origin Region
Brazil, Nepal, Madagascar, Switzerland, and the United States (Appalachian Mountains). Nepal produces the highest gem-quality blue material.
Hardness & Durability
Notable for extreme anisotropy: 4.5–5.0 along the length of the crystal and 6.5–7.0 across the width. Brittle toughness; sensitive to pressure and heat.
Care & Maintenance
Clean with warm soapy water and a soft cloth; avoid ultrasonic or steam cleaners. Store separately from harder gemstones to prevent scratching. Avoid chemical cleaners and prolonged direct sunlight.
Rarity & Value
Relatively common in mineral form, but high-clarity gem-quality material is rare. Value is determined by color intensity (vivid blues are best) and clarity. Generally affordable as tumbled stones.
Special Characteristics
Highly anisotropic hardness (different hardness depending on the direction of testing). Exhibits occasional chatoyancy (cat's eye effect) in rare specimens due to its fibrous structure.
Lore & History
Historically known as 'Cyanite'. In metaphysical lore, it is believed to be one of the few stones that does not accumulate or retain negative energy, used traditionally for the Throat and Third Eye chakras. It was used as a compass mineral by travelers in the past, believing it could hang from a hair and track the Earth's magnetic force.