Prasiolite is a pastel green variety of Quartz, often incorrectly called "Green Amethyst." Rarely found in Nature; artificially produced Prasiolite is heat treated Amethyst. Most Amethysts turn yellow/orange when heated producing Citrine, but some Amethyst will turn green when treated. Currently, almost all Prasiolite on the market results from a combination of heat/ionizing radiation treatment.