Main index --- Minerals list --- Other Minerals index Andalusite
Name:Andalusite
Derivation:From Andalusia (Spanish province)
Formula: Al2SiO5
Description: A dark celtic cross on a paler translucent background.

Andalusite crystals sometimes show a cross if cut in a particular way. This is called chiastolite, from "chiasma" (Greek) cross. The black bit is a different mineral.

Another mineral with a cross shape is staurolite.

Larger pictures of Andalusite:

This is a slice which has been polished to show the cross caused by the crystal growth.

Andalusite

This specimen has been polished on one side and the other left rough. You can just make out the cross on the rough side.

Andalusite Andalusite

This specimen has been polished (tumbled), which doesn't show the cross effect as well.

Andalusite