Salvors searching for a sunken 17th-century Spanish galleon said they found a gold and emerald ring with a rectangular cut stone estimated at 10 karats while diving 35 miles west of Key West Thursday.
They say they believe it is from the Nuestra Senora de Atocha, which sank off the Florida Keys during a 1622 hurricane.
The ring was found by divers from Mel Fisher's Treasures, who were looking for the sterncastle of the Atocha.
They say that based on the stone's 2.7-by-2.5-centimeter size, and the value of other Atocha emeralds, the ring's value is approximately $500,000.
Two silver spoons and other artifacts were found with the ring. They were pulled up from the same area where the Fisher crew found a 40-inch gold rosary in March and a gold bar in April.
Fisher's company found more than $450 million in artifacts and treasure from the Atocha shipwreck in 1985, but they are still looking for the sterncastle.