A pink diamond unseen in public for more than seventy years has changed hands in Geneva. The 24-carat emerald-cut stone, set in a ring by Bulgari and known as the Bulgari Pink, sold for CHF 12.1 million, about $14.6 million, at Christie's Magnificent Jewels auction on Tuesday 10 November. The result landed in the middle of its CHF 10 million to CHF 15 million estimate, and the stone was the final lot of the evening.

The diamond came from a European noble family that had held it since the 1950s, when the consignor's great-grandparents acquired the rough stone in India. Christie's believes it originated in the Golconda mines, the historic source of some of the world's most celebrated diamonds. Graded Fancy Intense Pink with VVS2 clarity, it is a Type IIa stone, a category covering fewer than two in every hundred gem-quality diamonds.

Christie's global head of jewellery, Max Fawcett, described the year as a tremendous one for the house's jewellery department and said strong demand from around the world had carried the sale. The 112-lot auction at the Four Seasons Hotel des Bergues totalled more than $50 million, with the top nine lots each passing $1 million. The same sale also offered a private collection of nearly 300 twentieth-century jewels, including pieces by Bulgari, Cartier and Graff.

The result caps a remarkable week for Geneva's auction rooms. A day earlier, Christie's own rare watch sale set a house record at CHF 47.8 million, while Phillips' Geneva watch auction became the first live watch sale to pass $100 million. The full results of Geneva Luxury Week are due later this week.