Blue Kyanite Specimen on Crystal Obelisk
Kyanite (also known as Disthene) · Mineral Specimen / Decorative Stone
Crystal System
Triclinic; forms typically in elongated, tabular, bladed crystals that often radiate outwards in fan-like or steller aggregations (bladed habit).
Mineral Group
Silicates (Subgroup: Nesosilicates)
Chemical Formula
Al2SiO5
Formation Process
Metamorphic, formed primarily through the high-pressure regional metamorphism of pelitic (clay-rich) sedimentary rocks in subduction zones or mountain-building collisions.
About This Crystal
The specimen features a stunning, starburst cluster (radiating sheaf) of blue bladed kyanite crystals mounted atop a faceted, clear cut-glass or quartz-like obelisk stand. The kyanite displays various shades of mottled blue, from deep indigo to pale ice-blue, with a pearly to vitreous luster and characteristic translucent to opaque blade structures.
Physical Characteristics
Color ranges from medium to dark blue, often with white streaks or color zoning. Streak is white. Has perfect cleavage in one direction along the length of the blades. Fracture is splintery to uneven. Specific gravity is approximately 3.53 to 3.67. Tenacity is brittle, except along the cleavage plane where it is somewhat flexible in thin pieces.
Optical Properties
Biaxial negative with strong optical anisotropy. Refractive index ranges from 1.710 to 1.734. Shows noticeable pleochroism, displaying different shades of blue or colorless from different angles. Birefringence is strong (0.012 to 0.020).
Hardness & Durability
Origin Region
Notable sources include Brazil, Switzerland, Russia, Kenya, Myanmar, and the USA (North Carolina). Forms in aluminum-rich metamorphic environments.
Hardness & Durability
Notable for its extreme directional hardness anisotropy: Mohs hardness is approximately 4.5 to 5.5 parallel to the length of the blades, but only 6.5 to 7 across the width. This makes it challenging to cut and wear in jewelry.
Care & Maintenance
Avoid using ultrasonic or steam cleaners. Clean gently using warm soapy water and a soft cloth. Store separately to avoid scratching softer stones and to prevent damage to its delicate, perfect cleavage planes.
Rarity & Value
Common to Uncommon depending on crystal size and formation quality. High-grade deep blue bladed clusters mounted as decor fetch moderate prices. Generally untreated as synthetic kyanite has no commercial market.
Special Characteristics
Demonstrates dramatic directional hardness anisotropy (scratching easily in one direction and resisting scratching in another) along with striking radiating crystal formations (bladed steller habit).
Lore & History
Historically used as an alignment and energy-transmitting stone due to its bladed structure. In modern metaphysical practices, kyanite is believed to align all chakras automatically without holding negative energy, heavily associated with the throat chakra and communication. (Note: These are traditional belief systems and not scientifically validated properties.)