Commonly Understood as Green Amethyst. Prasiolite (Greek- Leek green stone) is not found in nature. It is produced in labs, by heating violet amethyst or yellowish quarts from the deposit of Montezuma in Minas Gerais, Brazil
It need to be heated at about 930 degrees F(500 degrees C). Other deposits of heatable amethyst have been reported in Arizona. In sunlight, color commonly fades.