Alongside kyanite and sillimanite, andalusite is one of the three aluminosilicates that may occasionally be encountered as gemstones. The crystals possess perhaps the strongest pleochroism in the gem world, with the cutting orientation and/or viewing direction giving rise to either a brownish-red, brownish-yellow or greenish hue.

Andalusite takes its name from the southern Spanish region of Andalusia, where it was first discovered. However, Brazil is now the primary producer of gem-quality material, with significant deposits also found in Sri Lanka, Russia and the United States.

Viridine is a manganese-containing subs-species of andalusite, which is noted for its bright yellowish-green coloration. Another variety, known as chiastolite, possesses a distinctive dark cross of graphite against a light gray background, and is of great interest to both mineral collectors and Christians alike.