Andalusite

Appearance:

Transparent yellow, green or brownish-red

Common variations...

Chiasolite (opaque, white/grey/yellow with Mohs' hardness of 5.0 - 5.5) which forms prisms, having a dark cross in cross-section.

Common confusions......

Chrysoberyl, smokey quartz and tourmaline.

Esoteric beliefs and associations...

Associated with religious fervour and spiritual enlightenment.

Physical properties...

Chemistry	Aluminium silicate
System/Structure	Orthorhombic (thick, long crystals, elongated and grainy aggregates)
Refractive Index	1.641 - 1.648
Specific Gravity	3.12 - 3.18
Mohs' Hardness	7.5