Most expensive diamond sold at auction
Who
CTF Pink Star
What
71,200,000 US dollar(s)
Where
Hong Kong ()
When

The CTF Pink Star, formerly known as the Steinmetz Pink and the Pink Star, an internally flawless pink 59.6–carat diamond, sold for HKD 553,037,500 ($71.2 m; £57.3 m), including buyer's premium, at a Sotheby’s auction in Hong Kong on 4 April 2017. The diamond, mined in 1999 by De Beers in Africa, was 132.5 carats in its rough state and took two years to cut and polish. Now, the oval-shaped diamond, the largest internally flawless or flawless fancy vivid pink diamond that the Gemological Institute of America (GIA) has ever graded, measures 2.69 cm by 2.06 cm (1.06 in by 0.81 in) and is mounted on a ring. The buyer was Hong Kong conglomerate Chow Tai Fook Enterprises, which has a chain of jewellery stores. They immediately renamed the diamond the CTF Pink Star in memory of the late Dr. Cheng Yu-Tung, father of the current chairman and founder of Chow Tai Fook.

On 12 November 2013, the Pink Star achieved 76,325,000 Swiss francs ($83.01 million; £52.07 million), including commission fees, when the hammer went down at Christie's auction house in Geneva, Switzerland. However the sale did not go ahead due to default by the anonymous buyer.