I’d only ever encountered mentions of orichalcum as a rare metal in Guild Wars 2, but it was a real thing, and an underwater archaeology team found 39 ingots of orichalcum just off the coast of Sicily near Gela:
Gleaming cast metal called orichalcum, which was said by Ancient Greeks to be found in Atlantis, has been recovered from a ship that sunk 2,600 years ago off the coast of Sicily.
The lumps of metal were arriving to Gela in southern Sicily, possibly coming from Greece or Asia Minor. The ship that was carrying them was likely caught in a storm and sunk just when it was about to enter the port.
“The wreck dates to the first half of the sixth century,” Sebastiano Tusa, Sicily’s superintendent of the Sea Office, told Discovery News. “It was found about 1,000 feet from Gela’s coast at a depth of 10 feet.”
He noted that the 39 ingots found on the sandy sea floor represent a unique finding.
“Nothing similar has ever been found,” Tusa said. “We knew orichalcum from ancient texts and a few ornamental objects.”
Indeed orichalcum has long been considered a mysterious metal, its composition and origin widely debated.
According to the ancient Greeks, it was invented by Cadmus, a Greek-Phoenician mythological character. The fourth century B.C. Greek philosopher Plato made orichalcum a legendary metal when he mentioned it in the Critias dialogue.