In 2015, a 2,600-year-old shipwreck discovered off the coast of Gela in southern Sicily was found to contain 39 ingots of a mysterious alloy that archaeologists believe is the ancient metal known as orichalcum, a metal that Plato described as decorating the walls of the temple of Poseidon in Atlantis. Upon re-examining the wreck, archaeologists have uncovered new artifacts, including a jar, two Corinthian helmets, and 47 additional ingots of the mysterious metal.

The actual nature of orichalcum has been a mystery for thousands of years: despite having been described in ancient literature as a gold-white metal, even the Romans were divided as to its composition, as an alloy of gold and copper, copper and tin, or perhaps an entirely unknown element altogether. The ingots found in the shipwreck at Gela have been found to be comprised primarily of an alloy of 75-80 percent copper and 15-20 percent zinc, a close match for ancient descriptions of orichalcum.

Today, scholars believe that orichalcum isn’t as valuable a metal as it was made out to be by ancient authors, but would still be useful in the creation of decorative objects. Until the discovery of the shipwreck at Gela, the metal hasn’t been found in any great quantity, preventing researchers from properly ascertaining the material’s importance.

"Nothing similar has ever been found," explains Sebastiano Tusa, Sicily’s superintendent of the Sea Office. "We knew orichalcum from ancient texts and a few ornamental objects."