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Andalusite [abbr. And ]
Year of discovery: 1798 (El Cardoso de la Sierra, Spain), 1890 (Japan)
Locality list: 404 localities of andalusite
- Al2SiO5
- [Al3+][Al3+][O|SiO4]6-
- Polymorph: Kyanite (High pressure, Triclinic)
- Polymorph: Sillimanite (High temperature, Orthorhombic)
- Al => Mn: Kanonaite (Series)
- Color: Gray, Pink, Green
- Streak: White
- Luster: Vitreous
- Diaphaneity: Transparent-Translucent
- Habit: Granular, Prismatic
- Cleavage: Perfect on {110} (2 planes), Indistinct on {100} (1 plane)
- Hardness: 6.5-7.5
- Density: 3.2
- System: Orthorhombic
- Group: mmm, Pnnm
- Lattice: a=7.8, b=7.9, c=5.6
Etymology: Andalucia district, Spain