Important Diamond ring. Photo: Sotheby's

Claw-set with a brilliant-cut diamond weighing 10.64 carats, on a plain white gold mount, size 54. Estimate 370,000—570,000 CHF. Lot Sold 1,202,500 CHF

Accompanied by GIA report no. 1132191696 stating that the diamond is E Colour, VS1 Clarity.

Attractive Pair of diamond pendants. Photo: Sotheby's

Each set with a pear-shaped diamond weighing respectively 9.43 and 9.47 carats, to a surmount set with similar smaller stones, French maker's marks. Estimate 500,000—860,000 CHF. Lot Sold 902,500 CHF

Accompanied by GIA reports no. 5131243907 and no. 5131243935 stating that both diamonds are F Colour, VS2 and SI1 Clarity respectively.

Important Diamond ring, M. Gérard. Photo: Sotheby's

The cushion-shaped diamond weighing 9.76 carats, the shoulders set with similar stones, mounted in yellow gold, size 51½, signed M. Gérard and numbered, French assay and maker's marks. Estimate 325,000—500,000 CHF. Lot Sold 722,500 CHF

Accompanied by GIA report no. 2135282886 stating that the diamond is F Colour, VVS2 Clarity, together with an additional GIA worksheet stating that the diamond may be improvable after repolishing.

Diamond necklace, Bulgari. Photo: Sotheby's

Designed as a graduated row of heart-shaped diamonds, length approximately 405mm, signed Bulgari, case. Estimate 210,000—255,000 CHF. Lot Sold 254,500 CHF

Diamond ring, Bulgari. Photo: Sotheby's

The step-cut diamond weighing 7.40 carats, the shoulders set with baguettes, mounted in platinum, size 48, signed Bulgari. Estimate 85,000—130,000 CHF. Lot Sold 230,500 CHF

Diamond brooch, Van Cleef & Arpels. Photo: Sotheby's

Designed as a stylised posy, set with pear-shaped and brilliant-cut diamonds, to an articulated stem of baguette and tapered baguettes, mounted in platinum, signed Van Cleef & Arpels and numbered, French assay and maker's marks. Estimate 38,000—52,000 CHF. Lot Sold 74,500 CHF

Pair of diamond clips, Cartier, circa 1930. Photo: Sotheby's

Each of geometric and shield-shaped design, set with circular-cut and baguette diamonds, signed Cartier Paris and numbered, French assay and maker's marks. Estimate 18,500—28,000 CHF. Lot Sold 43,750 CHF

Sotheby's. Magnificent Jewels and Noble Jewels, 17 May 11, Geneva www.sothebys.com