A cornelian and gold necklace, by Lalaounis. Photo Christie's Image Ltd 2013

Centering upon an oval-shaped cornelian intaglio depicting Echidna stealing the horses of Hercules, to the two gold ropes gathered by two flowerheads, intaglio from the early 19th Century, necklace of modern make, 41.0 cm, in dark brown leather fitted case, the lid bearing the inscription 'Ex collection Prince Poniatowski - Sold Christie's April-May 1839'. Signed Lalaounis, no. A27. Estimate CHF10,000 – CHF15,000

Christie's. MAGNIFICENT JEWELS. 15 May 2013. Geneva