Art Deco and Art Nouveau were two distinct artistic styles. Art Deco refers to the geometric style popular between 1915 and 1935. Art Nouveau was introduced during the Edwardian period, from 1890 to 1910. Art Nouveau engagement rings feature flowing, natural designs, such as leaves and flowers. Art Nouveau rings are also known for their stunning enamel work, which gives them the look of small stained glass pieces. While Art Deco rings were often made of platinum and diamonds, Art Nouveau engagement rings were more likely to be white or yellow gold and were set with stones such as amethyst, amber, or pearl. Modern Art Nouveau rings often replace these stones with diamonds, but keep the delicate, sweeping lines of the Art Nouveau style.