Bonhams has announced that it will offer an extremely rare blue diamond in its Fine Jewellery auction on April 24.
The fancy deep-blue diamond, weighing 5.3 carats and set into a 1965 Bulgari ring, will sell for an estimated £1m-1.5m ($1.5-2.3m). It echoes the famous, and much larger, Hope Diamond of King Louis XIV of France, which is currently housed in the Smithsonian Natural History Museum.
Fancy diamonds are the most sought after for collectors, with the colour "fancy deep-blue" one of the rarest. They are "structurally very pure and account for less than 1% of all diamonds mined", according to Bonhams.
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