A new amethystine chalcedony has been discovered in Arizona. The material, marketed under the trade name "Damsonite," is excellent for both jewelry and carvings. The authors describe the gemological properties of this new type of chalcedony, and report the effects of heat treatment on it. Although this purple material is apparently a new color type of chalcedony, it has the same gemological properties as the other better-known types. It corresponds to a microcrystalline form of amethyst which, when heat treated at approximately 500°C becomes yellowish orange, as does some single-crystal amethyst.