Gustave Roger Sandoz Art Noveau Enamel and Opal Brooch in 18k yellow gold, circa 1900

Design as a fan-shaped frame, decorated with blue, green, orange and purple enamel, decorated with foliate scroll, suspending an opal drop, mounted in 18k yellow gold. Signed G. R. Sandoz for Gustave-Roger Sandoz, circa 1900.