An emerald, pearl and diamond necklace

The multiple strands of 2.9 - 4.8mm pearls, to circular clasp / pendant with a scalloped outline, centrally featuring a circular cabochon emerald and old brilliant-cut diamond cluster, within a surround of 4.1-4.8mm pearls, each inset with a circular-cut diamond, and a further surround of old brilliant-cut diamonds, suspending an emerald drop, diamonds approx. 3.15 carats total, partially struck maker's mark, Austrian assay mark, pearls untested, lengths: clasp / pendant 5.0cm, necklace 42.1cm