An emerald recovered from a shipwreck is set to be auctioned in New York.

The gemstone was discovered around 40 years ago off the coast of Florida in the ship "Nuestra Señora de Atocha", which sank in 1622, the auction house Sotheby's announced on Monday.

It now belongs – cut and on a ring – to the author Mitzi Perdue, who once got it as an engagement gift from her husband Frank Perdue, who died in 2005.

Proceeds from the auction scheduled for December 7 will be donated to humanitarian aid in Ukraine.

The gemstone is expected to sell for around $70,000.