Andalusite

Name:
Andalusite
Detailed information:

M Formula:	Al2OSiO4
Properties:
Gray, greenish, reddish, or bluish in color. D 3.1–3.2, hardness 7–7.5.
Occurrence:
Massachusetts, Connecticut, California, Nevada, Europe, South Africa, Australia.
Use:
Constituent of sillimanite refractories, sparkplug insulators, laboratory ware, superrefractories.