Andalusite
Mineral Al2SiO5
Also called Cross stone and Viridine
About it
Square-sectioned prisms in schist and hornfels; chiastolite shows a dark cross when cut across. Gem andalusite from Brazil flashes green and orange from different angles.
- Type
- Mineral
- Group
- Silicate (nesosilicate), andalusite group
- Formula
- Al2SiO5
- Hardness (Mohs)
- 6.5–7.5
- Specific gravity
- 3.13–3.21
- Streak
- white
- Lustre
- vitreous (glassy)
- Crystal system
- Orthorhombic
- Colours
- pink, red-brown, grey, green, white
- Transparency
- transparent, translucent, opaque
- Cleavage and fracture
- good in two directions (prismatic)
Typical values: real specimens vary. For more, see mindat.org.