New York: A “perfect” 100-carat diamond in a classic emerald-cut could fetch between $19 million (Dh70 million) to $25 million (Dh92 million) at auction.

“This 100.20-carat diamond is the definition of perfection. The colour is whiter than white. It is free of any internal imperfections,” Sotheby’s New York jewellery department head Gary Schuler said in a statement, likening its transparency “to a pool of icy water.”

The internally flawless D colour stone is the only classic emerald-cut white diamond of the highest colour and clarity and over 100 carats to come to auction, according to Sotheby’s, which will sell the diamond on Tuesday.

The diamond was mined in southern Africa within the last 10 years and weighed over 200 carats before it was cut and polished, the auction house said.

The owner wished to remain anonymous.

Only five “perfect” diamonds over 100 carats have sold at auction in the last 25 years, with a 118-carat oval-cut stone fetching $30.6 million at Sotheby’s in 2013. It set a record for a white diamond.

A record for any diamond is $46 million for a 24.78-carat emerald-cut pink stone, set at Sotheby’s in 2010. It also set a record for any jewel at auction.