Properties
| Category | Nesosilicates |
|---|---|
| Formula | Al2SiO5 |
| Crystal system | Orthorhombic |
| Color | Pink, violet, yellow, green, white, gray; in thin section, colorless to pink or green |
| Crystal habit | As euhedral crystals or columnar aggregates having nearly square cross sections; fibrous compact to massive |
| Cleavage | Good on {110}, poor on {100} |
| Fracture | uneven to subconchoidal |
| Mohs scale hardness | 6.5–7.5 |
| Luster | Vitreous |
| Streak | White |
| Diaphaneity | Transparent to nearly opaque with inclusions |
| Specific gravity | 3.17 (± .04) |
From the Wikipedia article
Andalusite is an aluminium nesosilicate mineral with the chemical formula Al2SiO5. This mineral was called andalousite by Delamétherie, who thought it came from Andalusia, Spain. It soon became clear that it was a locality error, and that the specimens studied were actually from El Cardoso de la Sierra, in the Spanish province of Guadalajara, not Andalusia.
Source
Source record: crystal-compendium/andalusite/minerals.json. Fetched from English Wikipedia by the operator 2 October 2026.
https://en.wikipedia.org/wiki/Andalusite — revision id 1356696698. Text and properties from Wikipedia, licensed CC BY-SA 4.0.