A diamond and enamel brooch / pendant, late 19th century

Of domed openwork design, set with a raised central cluster of old brilliant-cut diamonds within a geometric and scroll surround decorated with black enamel and old brilliant and rose-cut diamonds, suspending a palmier-link swag, with similarly-set accents and drops, detachable brooch fitting, old brilliant-cut diamonds approx. 3.70 carats total, length 9.9cm, cased