mineral
Blue Kyanite
Kyanite (Al2SiO5)
Hardness (anisotropic): 4.5-5 parallel to the long axis and 6.5-7 perpendicular to it; Color: Light to dark blue, white, or gray; Luster: Vitreous to pearly; Crystal structure: Triclinic; Cleavage: Perfect in one direction.
- Color
- Light to dark blue, white, or gray
- Luster
- Vitreous to pearly
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Physical properties
Hardness (anisotropic): 4.5-5 parallel to the long axis and 6.5-7 perpendicular to it; Color: Light to dark blue, white, or gray; Luster: Vitreous to pearly; Crystal structure: Triclinic; Cleavage: Perfect in one direction.
Formation & geological history
Formed through the regional metamorphism of clay-rich sedimentary rocks under high pressure. It is typically found in gneiss, schist, and pegmatites.
Uses & applications
Used in the manufacturing of heat-resistant ceramics (refractories), porcelain, and abrasive wheels. Also popular as a gemstone and in metaphysical healing practices.
Geological facts
Kyanite is highly anisotropic, meaning its hardness varies significantly depending on the direction in which it is scratched. It is an index mineral for high-pressure metamorphic environments.
Field identification & locations
Identify by its bladed crystal habit, distinct blue color, and characteristic variation in hardness. Commonly found in Brazil, Switzerland, Myanmar, and the USA (North Carolina).
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Mineral
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Mineral/Rock