Largest vivid blue diamond expected to sell for $45 million at auction

A legendary diamond is up for grabs.

This is the largest vivid blue diamond ever to come to auction. It's almost 15 carats in a classic emerald cut and is considered one of the rarest gems in the world.

It was owned by the late Sir Philip Oppenheimer, part of the family that controls the London based De Beers mining company.

It's expected to sell for as much as $45 million next month in Geneva.