Sotheby's flawless Blue Moon diamond, a 12.03ct will be the largest ever blue diamond ever to appear at auction. It was cut from a 29.62 rough blue, found by Petra Diamonds at the South African Cullinan mine in Jan 2014. It was purchased by Cora International and took 6 months to cut and polish. Estimates for auction will be between $35 and $55 million.
Natural Blue diamonds are so rare. This blue diamond is enhanced and treated. The treatment can only work with a small minority of diamonds, and involves irradiating them causing the colour change, usually followed by heat treatment to stabilise the colour.
Superb and Rare Fancy Vivid Blue Diamond and Diamond Ring Set with an oval brilliant-cut diamond weighing 10.10 carats, flanked by two pear-shaped diamonds, to the circular-cut diamond surround, gallery and hoop, mounted in 18 karat white gold