A gold, enamel and diamond locket pendant

A gold, enamel and diamond locket pendant, mid 19th century, the oval gold locket with a design of a flower in reserve against blue enamel, its petals set with rose-cut diamonds, the reverse with an anchor in blue enamel, each within a border of incised floral scrolls, opening to reveal a portrait miniature and the inscription 'AW to AM, 11th August 1856', length 3.8cm including bail