Andalusite is a polymorph with two other minerals, Kyanite and Sillimanite. It shows flashes of several different earth tones in the same stone. Because of its combination of colors, it has been called "poor man's alexandrite," but it does not look like alexandrite at all. Andalusite typically occurs in thermally metamorphosed pelitic rocks, and in pelites that have been regionally metamorphosed under low-pressure conditions.

Andalusite has very strong trichroism; if you examine the green stones carefully, you can see green running in one direction and a reddish brown color in the other direction.