This giant pink diamond could sell for $30 million at auction

• Sotheby's on Wednesday will auction a ring featuring an extremely rare 37.30-carat pink diamond.
• "The Raj Pink" is the world's largest known fancy intense pink diamond.
• The auction house estimates that the diamond will sell for $20 million to $30 million.

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.

The gem, called ‘The Raj Pink,’ is the world’s largest known Fancy Intense Pink diamond is expected to fetch up to $30 million at auction.

Source: Sotheby's

Before arriving in Geneva, the stone traveled around the world — from Hong Kong to London to New York, according to O'Connor.

Watch an all new episode of "Secret Lives of the Super Rich" Thursday at 10 p.m. ET/PT on CNBC.