An Edwardian amethyst necklace

An Edwardian amethyst, seed pearl and demantoid garnet necklace, early 20th century, the front composed of sinuous scrollwork in the Art Nouveau style, set with half seed pearls, oval amethysts and circular-cut demantoid garnets, to a fine back chain with barrel clasp, mounted in gold, necklace length 39cm, length at front 4.1cm, fitted case stamped Mappin & Webb