A diamond and seed pearl necklace

A diamond and seed pearl necklace, circa 1920, the centre designed as a swirled openwork cluster of circular-cut diamonds, mounted in platinum, to a necklace composed of eight strands of seed pearls meansuring approximately 3mm, necklace length 37cm, central motif diameter 3.2cm, detaching to form a brooch, or attaching as a pendant to a later 18ct white gold collar, British hallmarks, pearls untested, case