mineral
Kyanite
Al2SiO5
AI-generated identification · may be incorrectHardness varies from 4.5 parallel to the blade and 6.5 across; blue, gray, or greenish; vitreous to pearly luster; triclinic crystal system with perfect cleavage.
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Physical properties
Hardness varies from 4.5 parallel to the blade and 6.5 across; blue, gray, or greenish; vitreous to pearly luster; triclinic crystal system with perfect cleavage.
Formation & geological history
Forms primarily in aluminum-rich metamorphic pegmatites and schists through the alteration of clay minerals under high pressure.
Uses & applications
Used in the manufacture of refractory products, ceramics, and occasionally cut into collector gemstones.
Geological facts
Kyanite is well-known for its extreme anisotropy, meaning its hardness is dramatically different depending on the direction it is tested.
Field identification & locations
Identified by its distinctive bladed crystal habit, striated faces, and variable hardness; commonly found in Brazil, Switzerland, and the USA.
