Experts said the pink diamond is close to flawless with a classic emerald cut and gently rounded corners.
If sold for the estimated price, the pink diamond would top the previous record set when a blue 35.56-carat diamond was sold for $24.3 million in 2008.
Sotheby's did not identify the current owner of the pink diamond.
Other items that will be on sale at the Nov. 16 auction include a ruby and /*diamond*/ bangle, necklace and clip earrings once owned by Christina Onassis, the daughter of the Greek shipping tycoon Aristotle Onassis, and an emerald and diamond bracelet belonging to Cristina Ford, the second wife of Henry Ford's grandson Henry Ford II.
The Associated Press Contributed to this report.