A French Collier d'Esclavage necklace set with moss agate, the oval concave plaque with bevelled surround is set with a low dome moss agate cabochon, encircled by a row of seed pearls, further engraved with a geometrical frame, attached to two draping strands of cut-out and etched fancy links, fastened with a curved box clasp, yellow metal stamped with French poinçon marks, plaque measures 3.5 cm across, overall measuring 38.0 cm, cased in a tooled jewellery case, satin lining printed "Guillot Frères, Joailliers, Bijoutiers, 19 rue des Moulins, Paris".