Andalusite

Physical Properties

Color brown
Form/Habit elongated square prismatic
Lusture vitreous
Streak white
Hardness 7.5
Cleavage poor 2 sets rarely seen
Fracture conchoidal
Specific Gravity 3.8 (moderate)
Chemical Composition Al2SiO5
Crystal System orthorhombic
Diagnostic Properties elongated prismatic habit, rarely seen poor 2 sets cleavage

Remarks

Gallery