Properties
| Category | Nesosilicate |
|---|---|
| Formula | Al2SiO5 |
| Crystal system | Triclinic |
| Color | Blue, white, rarely green, light gray to gray, rarely yellow, pink, orange, and black, can be zoned |
| Crystal habit | Columnar; fibrous; bladed |
| Cleavage | perfect imperfect with 79° angle between |
| Fracture | Splintery |
| Tenacity | Brittle |
| Mohs scale hardness | 4.5–5 parallel to one axis ; 6.5–7 perpendicular to that axis |
| Luster | Vitreous to white |
| Streak | White |
| Diaphaneity | Transparent to translucent |
| Specific gravity | 3.53–3.65 measured; 3.67 calculated |
From the Wikipedia article
Kyanite is a typically blue aluminosilicate mineral, found in aluminium-rich metamorphic pegmatites and sedimentary rock. It is the high pressure polymorph of andalusite and sillimanite, and the presence of kyanite in metamorphic rocks generally indicates metamorphism deep in the Earth's crust. Kyanite is also known as disthene or cyanite.
Source
Source record: crystal-compendium/kyanite/minerals.json. Fetched from English Wikipedia by the operator 2 October 2026.
https://en.wikipedia.org/wiki/Kyanite — revision id 1325813730. Text and properties from Wikipedia, licensed CC BY-SA 4.0.