A staff member holds a 100-carat perfect diamond in a classic emerald-cut at Sotheby’s auction house in central London

A staff member holds a 100-carat perfect diamond in a classic emerald-cut at Sotheby’s auction house in central London

A staff member holds a 100-carat perfect diamond in a classic emerald-cut at Sotheby’s auction house in central London, February 13, 2015. The diamond is expected to fetch between $19-25 million at the auction house’s Magnificent Jewels auction in New York on April 21. REUTERS/Stefan Wermuth (BRITAIN – Tags: BUSINESS SOCIETY WEALTH)