Bonhams sold two major jewelry pieces for seven-figure amounts at auctions in New York and London in the past week.

  Graff Diamonds won a pear-shaped, 4.03-carat, fancy-intense blue diamond (pictured) for $3.6 million (GBP 2.7 million) at the Bonhams Fine Jewellery sale in London last Wednesday, the auctioneer said. The selling price — which smashed Bonham’s pre-sale high estimate of about $2 million — worked out at $853,203 per carat. The piece, which has been in a private collection for almost 30 years, was the subject of fierce bidding, Bonhams said. 

  Meanwhile, a private US buyer spent $1.8 million, or $106,509 per carat, on a step-cut, 16.90-carat, D-color, internally flawless diamond at Bonhams New York last Tuesday.