λ A superb pearl, enamel and diamond mourning ring, circa 1791

λ A superb pearl, enamel and diamond mourning ring, circa 1791, of oval outline, centring on a funerary monument composed of an ivory panel initialed ID, surmounted by a pearl, to a rose-cut diamond base, beneath a three-dimensional weeping willow set with rose-cut diamonds, on a blue enamel ground, covered by a glazed panel, to an outer border of cushion-shaped diamonds, the reverse with a glazed compartment containing hairwork, bordered by the dedicatory inscription 'Ja.s Duberly Esq died 4 July 1791 Aged 64', mounted in silver and gold, size Q1/2, front measuring 3.5 x 2.1cm, pearl untested