Cultured pearls, coral, onyx and diamond necklace, Mikimoto. Estimate HK$50,000 - 100,000 (US$6,400 - 12,800). Photo Tiancheng International

The necklace composed of numerous coral, cultured pearl and onyx beads, to the front inset with corals and onyx with brilliant-cut diamonds, completed by a similarly-set clasp, the diamonds together weighing approximately 1.50 carats, mounted in 18 karat white gold, signed, length approximately 420mm.

Coral beads measuring approximately 9.69 to 9.04mm; onyx beads approximately 9.97 to 9.38mm; cultured pearl beads approximately 8.91 to 8.49mm. 

Tiancheng International. HONG KONG AUTUMN AUCTION, Jewellery and Jadeite