mineral
Kyanite
Al2SiO5
AI-generated identification · may be incorrectHardness varies significantly from 4.5 parallel to the blade length to 6.5 across it. Typically blue, vitreous to pearly luster, and crystallizes in the triclinic system.
Identified More mineral →
Explore Kyanite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness varies significantly from 4.5 parallel to the blade length to 6.5 across it. Typically blue, vitreous to pearly luster, and crystallizes in the triclinic system.
Formation & geological history
Forms primarily in aluminum-rich metamorphic pegmatites and gneisses resulting from regional metamorphism of pelitic rocks under high pressure.
Uses & applications
Used extensively in the manufacture of refractory products, ceramics, and occasionally cut into collector gemstones.
Geological facts
Kyanite is well-known for its extreme directional hardness anisotropy, making it harder to scratch in one direction than another.
Field identification & locations
Identified easily by its distinctive bladed crystal habits, varying hardness, and vibrant blue coloration; found globally in Brazil, USA, and Switzerland.
