Andalusite varies in colour from the pale yellowish brown to some dark bottle-green, dark brown, or typically the most popular greenish red. It's quite strong and distinctive pleochroism, to ensure that, when turned, exactly the same stone can take place yellow, green and red. Large crystals might be vertically striated prisms having a square cross-section and pyramidal ends, but they are rare. More usual are opaque, rod-like aggregates of crystals or waterworn pebbles. It's the pebbles which are usually cut as gemstones. Andalusite is generally present in pegmatites. Pebbles occur within the gem gravels of Sri Lanka and Brazil. Other localities include Spain, Canada, Russia, Australia and the united states. An opaque, yellowish grey variety, chiastolite, occurs so long prisms, which will make a cross when cut and polished.
