An early Victorian half pearl and blue enamel mourning ring

An early Victorian half pearl and blue enamel mourning ring, the central half pearl set star with a blue enamelled ground, to crossover half pearl set shoulders, the reverse engraved Mary H. St.John died Oct. 31, 1851, Aged 76 years, to an articulated expandable blue enamelled shank, finger size J 1/2 (unexpanded), 4.9g gross

One of the hinged sections by the front panel is missing a pin