A 4.03-carat fancy intense blue diamond is headlining Bonhams London Fine Jewelry sale in September. The auction will also feature a fancy grey-blue diamond and a Kashmir sapphire ring, among other notable pieces.
The fancy intense blue diamond is expected to fetch £1,200,000 to £1,500,000 (around US$1.53 million to US$1.91 million). The pear-shaped diamond has been in a UK private collection for over 30 years, according to Bonhams.
Citing a report by the Gemmological Institute of America, the auction house said only one in 10,000 diamonds has a fancy colour, which makes such stones rare and highly sought after.
Often referred to as “miracles of nature,” fancy colour diamonds have, on average, increased in value by 100 percent over the past decade with blue stones showing the strongest growth over the past 12 months at more than 5.5 percent, according to the Knight Frank Luxury Investment Index.
Jean Ghika, head of Jewelry for Bonhams UK and Europe, said: “We are delighted to bring this exceptional stone to the market. Blue diamonds are extremely rare and highly coveted. We are looking forward to showcasing this stone, along with other selected lots in London, New York, Hong Kong and Geneva, where we anticipate considerable interest.”
The September sale will include 188 lots, including a selection of white and fancy colour diamonds; sapphires from Kashmir, Burma and Sri Lanka; signed jewellery from Cartier and Van Cleef & Arpels; and the largest private collection of jewellery ever to come to auction by Anglo-Italian designer Andrew Grima.
Another highlight of the sale is a fancy colour diamond brooch. This features a central square step-cut fancy grey-blue diamond, weighing 4.83 carats, with a fancy dark brown-greenish yellow step-cut diamond to either side, weighing 2.51 carats and 2.38 carats, respectively, suspending a pear-shaped fancy pink diamond drop, weighing 1.90 carats. The brooch dates from the mid-20th century and has a pre-sale estimate of £650,000 to £850,000 (around US$831,000 to US$1.09 million).
A Kashmir sapphire single-stone ring, weighing 9.61 carats, is also expected to command attention at the sale. The octagonal step-cut sapphire has no indications of heating, noted Bonhams.