Green is one of 50 identified colors of decorative glass with an iridescent surface shimmer known as carnival glass. The manufacturer molds or presses green base glass with a pattern and applies many kinds of metallic salts, producing a metallic shine.
Color classifications go by the base color of the glass, before application of the iridizing mineral salts. Marigold, blue, red and amethyst are other common colors of this collectible glass. Huge volumes of carnival glass were produced in the 1920s at the height of its popularity. Collectors named it carnival glass in the 1950s because it was sometimes given as prizes at carnivals and fairs. The less common colors are most prized by collectors today.