An ultra-rare 5.3-carat fancy deep-blue diamond ring, which is expected to fetch upwards of $2.4 million, will be the top lot at Bonhams Fine Jewelry sale in London on April 24. Designed circa 1965 by Bulgari, the renowned Italian designer, the distinctive Trombino-style ring features a cushion-shaped blue diamond set horizontally. The ring is accented with pavé-set brilliant-cut diamonds and courses of baguette-cut diamonds.
The upcoming sale is already causing a buzz in jewelry and auction circles. Blue diamonds are extremely rare in the market and command some of the highest prices at auction worldwide. The term “fancy” refers to the intensity of color and the rating of “fancy deep-blue” is one of the rarest — and most coveted.
The extraordinary blue hue is derived from small atoms of boron mixing with the carbon atoms in a diamond. This anomaly affects the absorption of light passing through the stone and gives it a blue appearance.
"Blue diamonds, especially those over 5 carats, are extremely rare to see on the market and continue to be highly sought after," said Jean Ghika, Director of Bonhams Jewelry Department for the UK and Europe. "During the 1960s and 1970s, Bulgari was well known for its imaginative settings and use of colored diamonds. This ring epitomizes that 'golden era' of elegant simplicity and we are honored to be handling the sale of such a unique gem."
Despite their extreme rarity, other blue diamonds have been in the news recently. In November 2012, Sotheby's Geneva sold a 10.48-carat fancy deep-blue briolette-shaped diamond for $10.9 million. In April of 2012, Sotheby's Hong Kong was the site of another high-profile blue diamond sale at which an 8.01-carat emerald-cut fancy vivid-blue diamond ring fetched $12.7 million.