KEY INSIGHTS
📜 Plato mentions orichalcum exactly twice, both in the Critias, both describing a city he almost certainly invented.
⚗️ The leading identification is brass (copper-zinc alloy), a material ancient metalworkers produced without understanding the chemistry behind it.
🚢 In 2015, divers recovered 39 ingots of a copper-zinc alloy from a 6th century BC shipwreck off Gela, Sicily.
🎮 Roughly 75 per cent of search traffic for "orichalcum" comes from gamers who know it as a crafting material in Skyrim, Assassin's Creed, and similar titles.
❌ Plato says orichalcum was "now only a name" in his own time, which most likely means he borrowed a poetic word for a mundane alloy to make Atlantis sound exotic.
Orichalcum: Plato's Mystery Metal
A word that meant something once. Or possibly nothing at all.
📜 Academic sources for this section ▾
1. Plato. Timaeus and Critias. Translated by Robin Waterfield. Oxford University Press, 2008.
2. Healy, J.F. Mining and Metallurgy in the Greek and Roman World. Thames and Hudson, 1978.
Orichalcum is a metal mentioned by Plato in the Critias, where he describes it as the material used to clad the walls of Poseidon's temple in Atlantis. He calls it second only to gold in value and notes it was "now only a name" in his own day. The most widely accepted modern identification is brass, a copper-zinc alloy that ancient metalworkers produced by smelting copper with calamine ore. In 2015, 39 ingots of a copper-zinc alloy were recovered from a 6th century BC shipwreck off Gela, Sicily, reigniting debate over whether the material Plato described was a real alloy or a literary invention.
Plato's temple of Poseidon, walled in orichalcum. A philosophical set piece, not a travel guide.
What Plato Actually Wrote About Orichalcum
Two passages. Two thousand years of overinterpretation.
📜 Academic sources for this section ▾
1. Plato. Timaeus and Critias. Translated by Robin Waterfield. Oxford University Press, 2008.
2. Rosenmeyer, T.G. "Plato's Allegory of the Cave and the Allegory of Orichalcum." Classical Quarterly 6 (1956): 162–164.
The word orichalcum (Greek: oreíkhalkos, ὀρείχαλκος, literally "mountain copper") appears in Greek literature before Plato. Hesiod uses it in the Shield of Heracles to describe the greaves worn by the hero, and the Homeric Hymn to Aphrodite mentions earrings made from the material. In both cases the context suggests something precious, metallic, and decorative. Neither text explains what it actually was.
Plato's two references in the Critias (114e and 116c-d) are the ones that launched the modern obsession. He describes Atlantis as rich in a metal called orichalcum, "second only to gold in value," which the Atlanteans used to clad the inner walls of Poseidon's temple and the outer wall of the citadel. The surfaces "flashed with the red light of orichalcum." He then adds a crucial qualifier: the metal was "now only a name," suggesting it had either become rare or that his audience would not have encountered it.
This qualifier is the hinge of the entire debate. If orichalcum was a real material that had become scarce by Plato's time (around 360 BC), then the Gela shipwreck may have recovered examples of it. If Plato borrowed an archaic poetic word and assigned it to a fictional metal to make his fictional city sound impressively ancient, then searching for orichalcum in the archaeological record is looking for something that never existed outside a philosophical allegory.
Two sentences in the Critias. That is the entire ancient evidence for orichalcum's importance.
Three Theories: Brass, Gold Alloy, or Literary Invention
The candidates range from boring to imaginary.
📜 Academic sources for this section ▾
1. Craddock, P.T. "The Composition of Copper Alloys Used by the Greek, Etruscan and Roman Civilisations." Journal of Archaeological Science 5 (1978): 1–16.
2. Healy, J.F. Mining and Metallurgy in the Greek and Roman World. Thames and Hudson, 1978.
Brass (copper-zinc alloy) is the front-runner. Ancient metalworkers produced brass by smelting copper with calamine (zinc carbonate ore) in a process called cementation. The resulting alloy has a pale golden colour that could reasonably be described as "flashing with red light" depending on the copper-to-zinc ratio. Brass was known in the ancient world from at least the 3rd millennium BC, though systematic production became widespread only in the Roman period. The identification fits Plato's description of a gold-like metal that had become common enough to lose its mystique by the 4th century BC.
A gold-copper alloy is the second candidate. Electrum (gold-silver) and tumbaga (gold-copper, known from the Americas) both produce metals with a reddish-gold appearance. Some scholars have proposed that orichalcum was a copper-rich gold alloy, which would explain why Plato ranked it second to gold in value. The problem is that no such alloy has a strong presence in the Greek archaeological record, and "mountain copper" as a name makes more sense for a copper-based alloy than a gold-based one.
Pure literary invention remains a serious possibility. Plato's Atlantis narrative is not a historical account. It is a philosophical allegory about the corruption of an ideal society. Every detail, including the exotic metal on the temple walls, serves the story's rhetorical purpose. A metal that was "now only a name" is precisely the kind of evocative detail a skilled writer would invent to signal that Atlantis belonged to a vanished age fundamentally different from the present. The word already existed in poetry. Plato may simply have repurposed it.
Brass, gold alloy, or nothing at all. The evidence favours the least exciting option.
The Gela Shipwreck and What 39 Ingots Proved
International headlines said "orichalcum found." The evidence said something more careful.
📜 Academic sources for this section ▾
1. Tusa, S. and Royal, J. "The Landscape of the Naval Battle at the Egadi Islands." Journal of Roman Archaeology 25 (2012): 7–48.
2. Angelini, I. et al. "Chemical Analyses of Bronze Age Metal Artefacts from the Mediterranean." Journal of Cultural Heritage 34 (2018): 15–25.
In 2015, marine archaeologist Sebastiano Tusa announced the recovery of 39 metal ingots from a shipwreck off the coast of Gela, Sicily, dated to the 6th century BC. Chemical analysis revealed the ingots were a copper-zinc alloy, roughly 75 to 80 per cent copper and 15 to 20 per cent zinc, with traces of nickel, lead, and iron. The composition is consistent with brass produced by cementation. Tusa described the ingots as orichalcum, and the international press ran with it.
The discovery proved that copper-zinc alloys were being produced and traded in the central Mediterranean two centuries before Plato wrote the Critias. That much is significant. But the leap from "ancient brass ingots found on a shipwreck" to "Plato's legendary orichalcum recovered from the sea" requires assumptions the evidence does not support. We already knew ancient brass existed. The question was never whether copper-zinc alloys were real. The question is whether Plato's orichalcum referred to brass specifically, or whether he used an old poetic word to describe a fictional material in a fictional city.
The Gela ingots make the brass identification more plausible than it was before 2015. They do not confirm it. The most honest answer is that orichalcum was probably brass, Plato probably borrowed the name for literary effect, and the Gela shipwreck is a genuinely important find for the history of ancient metallurgy that got saddled with an Atlantis headline it did not need.
Thirty-nine ingots on the seabed. Ancient brass, not lost magic.
Bibliography
Primary Sources
Hesiod. Shield of Heracles. Translated by Hugh G. Evelyn-White. Loeb Classical Library, 1914.
Plato. Timaeus and Critias. Translated by Robin Waterfield. Oxford University Press, 2008.
Secondary Sources
Angelini, I. et al. "Chemical Analyses of Bronze Age Metal Artefacts from the Mediterranean." Journal of Cultural Heritage 34 (2018): 15–25.
Craddock, P.T. "The Composition of Copper Alloys Used by the Greek, Etruscan and Roman Civilisations." Journal of Archaeological Science 5 (1978): 1–16.
Healy, J.F. Mining and Metallurgy in the Greek and Roman World. Thames and Hudson, 1978.
Rosenmeyer, T.G. "Plato's Allegory of the Cave and the Allegory of Orichalcum." Classical Quarterly 6 (1956): 162–164.
Tusa, S. and Royal, J. "The Landscape of the Naval Battle at the Egadi Islands." Journal of Roman Archaeology 25 (2012): 7–48.
Pale gold with a copper undertone. Neither magical nor worthless. Just brass.
Copper plus calamine plus heat. The recipe for orichalcum was never lost. It was never mysterious.
