A gold, enamel and diamond snuff box, possibly France, mid 19th century, l possibly later

A gold, enamel and diamond snuff box, possibly France, mid 19th century, of oval outline, the lid set with an enamel portrait, possibly of the Marquise de Montespan after Jean I Petitot (1607-1691), to a border of rose-cut diamonds, within a frame of enamelled laurel leaves, against a blue guilloché enamel ground, the outer edge, side and base similarly enamelled, measuring 8.1 x 5.8 x 3cm, interior with partial French warden, decharge and maker's marks, portrait panel possibly later added, gross weight 161.5 grams, fitted case stamped Garrard & Co.