Andalusite is an alumino-silicate
mineral with the chemical formula Al
2SiO
5.
Andalusite is a common
metamorphic mineral which forms under high pressure and/or temperature. The minerals
kyanite and
sillimanite are polymorphs of andalusite, each occurring under different temperature-pressure regimes and are therefore rarely found together in the same rock. Because of this the three minerals are a useful tool to help identify the pressure-temperature paths of the host rock in which they are found.
- Kyanite
- Sillimanite
- Chiastolite[?]