A rare yellow diamond discovered in South Africa is expected to fetch up to $15 million when it goes to auction next week.

Officials with Sotheby's auction house say the pear-shaped diamond is believed to be the world's largest vivid yellow diamond.

The so-called Sun-Drop Diamond is just over 110 carats, or roughly the size of a woman's thumb.

It will go on sale in Geneva, Switzerland on Tuesday, when it is expected to sell for between $11 million and $15 million.

David Bennett, who works with Sotheby's jewelry division, said the stone has a very large “presence.” And he said it is even more desirable because the prized stone has never had a single wearer.

The diamond was discovered in South Africa in 2010 and is being sold by the New York-based diamond company Coral International.