The Bonhams Fine Jewellery sale slated on April 24, 2013, will include an extremely rare blue diamond ring in its lots on sale. The ring is characterized as a fancy deep-blue diamond set in a ‘Trombino’ ring made by Bulgari. The ring was made circa 1965 and features a cushion-shaped fancy deep-blue diamond, weighing 5.30 carats. It is set horizontally within a mount pavé-set with brilliant-cut diamonds and courses of baguette-cut diamonds. The ring is estimated to fetch £1,000,000 to 1,500,000 at auction.

Jean Ghika, Director of the Jewellery Department for the UK and Europe commented, “Blue diamonds, especially those over 5.00 carats, are extremely rare to see on the market and continue to be highly sought-after. During the 1960s and 70s Bulgari was well known for its imaginative settings and use of coloured diamonds making them one of the most innovative and fashionable jewellers of the time. This ring epitomises that ‘golden era’ of elegant simplicity and we are honoured to be handling the sale of such a unique gem.”

In September 2011, Bonhams sold a fancy vivid-blue diamond ring by Bulgari for £1,900,000. The ring was set with two pear-shaped diamonds, one white and the other fancy vivid-blue and generated interest more than doubling the pre-sale estimate.

Bonhams, founded in 1793, is one of the world's largest auctioneers of fine art and antiques.