Agate, Enamel and Diamond Desk Clock, Cartier, circa 1920

The circular engine-turned dial of ray design applied with translucent blue enamel, the hands set with rose-cut diamonds, the white enamel chapter ring featuring gilt Roman numerals, within a square frame of taupe agate applied with diamond-set initials ER and the numbers :1.6.23, strut back signed Cartier, Paris and numbered 809, movement unsigned, 2 7/8 by 2 7/8 inches.