mineral
Likely raw blue kyanite specimens
Kyanite, Al₂SiO₅
AI-generated identification · may be incorrectTypically blue, bladed crystals with vitreous to pearly luster and strong directional hardness: about 4.5 parallel to blades and 6.5–7 across them; perfect cleavage and triclinic structure. The image appears to show blue fragments on a mineral-rich slab, though exact identification is uncertain from the photograph.
- Hardness
- about 4
Identified More mineral →
Explore Likely raw blue kyanite specimens in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Typically blue, bladed crystals with vitreous to pearly luster and strong directional hardness: about 4.5 parallel to blades and 6.5–7 across them; perfect cleavage and triclinic structure. The image appears to show blue fragments on a mineral-rich slab, though exact identification is uncertain from the photograph.
Formation & geological history
Kyanite forms mainly in aluminum-rich metamorphic rocks, especially schist and gneiss, under medium- to high-pressure conditions during regional metamorphism. It commonly crystallized during Paleozoic to younger mountain-building events.
Uses & applications
Used as a refractory and ceramic raw material because it expands predictably when heated; attractive blue crystals are collected and occasionally used as cabochons or ornamental material.
Geological facts
Kyanite, andalusite, and sillimanite share the same composition but form under different pressure-temperature conditions. Its unusually directional hardness is a useful diagnostic feature.
Field identification & locations
Look for elongated blue blades, prominent cleavage, and hardness changing with direction; common sources include Nepal, Brazil, Switzerland, India, and the United States. A streak, hardness, and locality test would be needed to distinguish it from blue schorl, dumortierite, or corundum.
