A diamond ring watch, 1920s

A diamond ring watch, 1920s, the square silvered dial with black enamel indicators and blued steel hands, within an oval case set with rose-cut diamonds, to foliate shoulders, one shoulder opening via a hinge to conceal the winder, size P, front measuring 2.0 x 1.4cm, reverse numbered 616509, manual winding movement, Swiss and French import assay marks for 18ct gold