World's largest flawless diamond could sell for $20m or more

The diamond
The diamond

The largest flawless diamond ever to be auctioned is set to go under the hammer in May at Christie's in Geneva. It is expected to sell for a small fortune, because perfect diamonds like this are incredibly rare - and ones of this size are almost unheard of.

So what will it fetch, and how does it compare with the most expensive diamonds ever sold?%VIRTUAL-SkimlinksPromo%