A ring featuring an extremely rare 37.30-carat pink diamond is hitting the auction block Wednesday.
"The Raj Pink" is the world's largest known fancy intense pink diamond.
"Color diamonds are exponentially rarer than white stones," said Sotheby's international jewelry specialist Brett O'Connor. "The stone is … right up at the very top. It has size, it has brilliance, it has beauty."
Sotheby's plans to sell the ring at the Magnificent Jewels auction at the Four Seasons Hotel des Bergues in Geneva on Wednesday. The auction house estimates the diamond will sell for $20 million to $30 million.
The pink diamond has a cushion-modified shape, meaning it is neither completely rectangular nor round.