mineral
Blue Kyanite
Kyanite (Al2SiO5)
AI-generated identification · may be incorrectHardness: 4.5 parallel to the long axis and 6.5-7.0 perpendicular; Color: Blue-grey to sky-blue; Luster: Vitreous to pearly; Crystal structure: Triclinic; Cleavage: Perfect in one direction.
- Hardness
- 4
- Color
- Blue-grey to sky-blue
- Luster
- Vitreous to pearly
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Physical properties
Hardness: 4.5 parallel to the long axis and 6.5-7.0 perpendicular; Color: Blue-grey to sky-blue; Luster: Vitreous to pearly; Crystal structure: Triclinic; Cleavage: Perfect in one direction.
Formation & geological history
Forms in regional metamorphic environments where aluminum-rich sedimentary rocks (like shale) undergo high-pressure, low-temperature metamorphism.
Uses & applications
Used in the manufacture of heat-resistant ceramics, spark plugs, abrasive wheels, and as a gemstone for jewelry or metaphysical collecting.
Geological facts
Kyanite is strongly anisotropic, meaning it has two different hardness ratings depending on the direction it is scratched. It is one of the three polymorphs of Al2SiO5 alongside andalusite and sillimanite.
Field identification & locations
Identified by its distinctive bladed crystal habit and blue color. Common in metamorphic belts such as the Appalachian Mountains in the US, Brazil, and India.
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