A single-stone ring by Van Cleef & Arpels featuring a 10.28-carat, E colour, marquise-cut diamond is set to lead the Bonhams London Fine Jewellery sale on April 27. The ring has a pre-auction estimate of £150,000-£200,000 ($187,200-$250,000).

Accompanied by an additional letter from GIA, the diamond has been classified as Type IIa, meaning that it has been recognised as the most chemically pure and with exceptional optical transparency.

Signed jewellery from the world’s most famous houses will also be offered in the sale, which will consist of 141 lots in total. Notable pieces include a diamond 'fuchsia' brooch and earring suite by Van Cleef & Arpels. The brooch is designed as a fuchsia flower head, its petals pavé-set with brilliant-cut diamonds and its stamen reveals an articulated cascade of pear-shaped diamonds. Set with 27.05 carats of diamonds, the suite is estimated at £70,000-£100,000 ($87,000-$125,000).

Also on the block is an art deco diamond bracelet by Cartier, estimated at £20,000-£30,000 ($25,000-$37,500). Dated circa 1925 and signed Cartier Londres, the bracelet is designed as a finely pierced articulated strap of geometric design, decorated with cushion-shaped old brilliant and single-cut diamonds.

Another feature of the sale is an enamel and diamond 'Serpenti' bracelet-watch by Bulgari. This is a rare surviving example of the famed Bulgari Serpenti design bracelet watch, circa 1965-1970. The highly articulated bracelet is composed of a series of overlapping scales applied with orangey-yellow and red enamel. The serpent's head features a forked tongue and marquise-cut diamond eyes, its mouth opens to reveal a circular watch dial.

Inscriptions are often found on the underside of the tails of Bulgari Serpenti pieces, referring to specific species whose skins inspired the enamel work. This particular example is of a 'Serpe dei Ratti Giallo', or a Yellow Rat Snake, and has a pre-sale estimate of £50,000-60,000 ($62,400-$75,000).

https://www.gemkonnect.com/news/10-carat-marquise-diamond-ring-lead-bonhams-april-27-sale