A 24.78 pink diamond ring is set to be auctioned by Sotheby's in Geneva next month, and could go for as much as $38 million, according to the auction house.

The ring, whose pink diamond is color graded Fancy Intense Pin, was originally sold by jeweler Harry Winston 60 years ago and has been in private hands ever since.

David Bennett, Chairman for Europe and the Middle East at Sotheby's, said that the pink stone was "one of the most desirable diamonds" he has seen over the course of his 35-year career with the auction house. Bennett noted that the diamond's "exceptional" rose-pink hue and purity, combined with its emerald cut - more typical of white diamond jewelry - make it extremely unusual.