A lady's Art Deco diamond cocktail watch, 1920s, the rectangular silvered dial with black enamel

A lady's Art Deco diamond cocktail watch, 1920s, the rectangular silvered dial with black enamel indicators and blue steel hands, within a case of geometric design millegrain-set with circular-cut diamonds, accented to the sides with foliate engraving, to a mesh link bracelet, mounted in platinum and white gold, case width 1.4cm, manual winding movement, French assay marks for 18ct gold and platinum, French maker's mark JG with star, numbered 10831