In two auctions held close together – Bonhams London December Jewelry sale (December 5) and the Bonhams New York December Fine Jewelry sale (December 3) – Bonhams saw some very fine results for diamonds, gemstones and jewellery.

At the December 5, 2018 sale in London, a step-cut, D colour, Internally Flawless Type IIa diamond weighing 24.31 carats sold for £ 1,868,750 (US$ 2,387,105; or US$ 98,194 per carat).

“The diamond was the subject of fierce bidding in the saleroom, online, on the phones and eventually sold to a telephone bidder, exceeding its pre-sale estimate of £ 1,300,000 – 1,800,000 (US$ 1,700,000 –2,300,000),” Bonhams announced.

Emily Barber, Director of Jewelry at Bonhams UK, said: "This magnificent gem was greatly admired during our previews in London, New York, LA and Hong Kong. It attracted a lot of interest not only due to its significant size – top quality diamonds over 20 carats are very rare – but also due to its Internal Flawless clarity and its exceptional white colour. We're delighted with how well it performed."

The London sale raised a total of £ 5,201,000 (US$ 6,643,656). The auction house found that sapphires from Kashmir were also much in demand, with two notable lots selling during the sale.

These included: a late 19th century Sapphire a d Diamond Brooch which sold for £ 248,750 (US$ 317,748 or US$ 77,880 per carat), beating its pre-sale estimate of £ 120,000 - 180,000 (US$ 160,000 – 230,000); and a Sapphire and Diamond Ring by Asprey weighing 3.09 carats, sold for £ 87,500 (US$ 114,625 or US$ 37,095 per carat), also exceeding its pre-sale estimate of £ 60,000 - 80,000 (US$ 78,000 - 100,000).

Both Kashmir sapphires are accompanied by reports confirming no indications of heat treatment.

Barber noted: "Kashmir sapphires have continued to be in high demand from Bonhams' clients globally due to their rarity and because the finest specimens are the benchmark against which all other sapphires are judged."

The other notable performers were a fancy colour diamond and diamond ring and Van Cleef & Arpels jewellery.

In the New York auction on December 3, it was diamonds all the way with both fancy  colour and white stones doing well.

“The top performing lot during the two-hour sale was an Important Diamond Ring which sold for US$ 828,500 against its estimate of US$ 400,000-600,000,” reported Bonhams. “Coming from a private collection, this was the first time the 18.04 carats emerald-cut diamond had come to auction.”

Caroline Morrissey, Head of Sale, Bonhams Jewelry (US), said: "We saw some fierce bidding for this magnificent diamond and are delighted with how well it performed."

The second top performing lot was a Diamond Solitaire Ring by Royal De Versailles. The round, brilliant-cut diamond of F colour, VS1 clarity, weighing 7.01 carats, sold for US$ 275,000; exceeding its pre-sale estimate of US$180,000-250,000.

Pic Cap: The step-cut diamond, weighing 24.31 carats, within a four-claw setting  

Pic Courtesy: Bonhams