A Unique Opal, Blue Topaz, Amethyst and Diamond Necklace by Patrick Mauboussin. Photo courtesy Tiancheng International

Centring on a free - form opal, the necklace of jelly fish motif is pave - set with diamonds and blue topaz. Dangling eleven tentacles with the front seven interlocking with opals, amethysts and diamonds, the remaining four tentacles swirl into a neck chain set with diamonds, highlighted with multi - coloured stones. The opals, blue topaz, diamonds and amethysts and rhodolites weighing 83.07, 7.00, 4.00, 2.00 and 2.00 carats respectively, mounted in 18k white gold. Length 44.5 cm. With maker's mark M Paris for Patrick Mauboussin, No. 26739. Estimate HK$117,000 - 156,000US$15,000 - 20,000

Tiancheng International. Hong Kong Autumn Auction 2011. 28 Nov 2011 www.tianchengauction.com