mineral
Kyanite
Al2SiO5
AI-generated identification · may be incorrectHardness varies significantly from 4.5 parallel to the blade to 7 across it on the Mohs scale. Typically blue, gray, or greenish with a vitreous to pearly luster and a triclinic crystal 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 to 7 across it on the Mohs scale. Typically blue, gray, or greenish with a vitreous to pearly luster and a triclinic crystal system.
Formation & geological history
Forms primarily through the metamorphism of aluminum-rich clay-rich sedimentary rocks under high pressures and moderate temperatures, often in regional metamorphic terrains.
Uses & applications
Used primarily in the manufacture of refractory products, ceramics, and porcelain for high-temperature industrial applications, as well as occasionally faceted into collector gemstones.
Geological facts
Kyanite is one of the best examples of anisotropy in minerals, exhibiting drastically different hardness values depending on the direction of the scratch test.
Field identification & locations
Identified easily by its distinctive bladed, elongated crystal habit and extreme directional hardness variation. Commonly found in metamorphic schists and gneisses worldwide.
