Andalusite varies in color from a pale yellowish brown to a dark bottle-green, dark brown, or the most popular greenish red. It has very strong and distinctive pleoehroism, so that, when turned, the same scone may appear yellow, green, and red. Large crystals may be vertically striated prisms with a square cross-section and pyramidal ends, but are rare. More usual are opaque, rod-like aggregates of crystals or watchword pebbles. It is the pebbles that are usually cur as gemstones.

Andalusite is usually found in pegmatite's. Pebbles occur in the gem gravels of Sri Lanka and Brazil. Other localities include Spain, Canada, Russia, Australia, and the USA

An opaque, yellowish grey variety, chiastolite, occurs as long prisms, which make a cross when cur and polished.