A natural pearl, diamond, onyx and seed pearl necklace. Estimate HK$800,000 – HK$1,200,000 ($100,000-150,000). Photo Christie's Image Ltd 2015

The diamond roundel and seed pearl necklace, set with three oval-shaped brown natural pearls measuring approximately 11.6 x 11.9 to 12.3 x 14.3 mm, flanked by cone shape onyx, to the marquise-cut diamond clasp, mounted in platinum, 42.7 cm long

Accompanied by report no. 79650 dated 30 March 2015 from the SSEF Swiss Gemmological Institute stating that the analysed properties confirm the authenticity of these three saltwater natural pearls, with no indications of artificial colour modification

Christie's. HONG KONG MAGNIFICENT JEWELS, 2 June 2015, Hong Kong