According to Plato's dialogue Critias, one of the more notable natural resources of the Lost Continent of Atlantis was a material called orichalcum. It was mined there and had a reddish hue. It was used to decorate the Temple to Poseidon and Cleito and a pillar of solid orichalcum stood in the center of the temple, inscribed with the Laws of Poseidon and records of the early princes of the city. It's value was second only to gold.
The word turns up in a couple other ancient sources. The Greek poet Hesiod mentions it in the 7th Century BC, pre-dating Plato. The Jewish historian Josephus stated that the sacred vessels of the Temple of Solomon were made of orichalcum and the Roman writer Pliny the Elder that the stuff wasn't around any more because the mines are exhausted.
But what was it? Nobody knows. The word in Greek means "mountain copper" or "mountain metal." Critias, telling the story of Atlantis in the dialogue, says that in his day orichalcum is "only a name". Presumably, the only source of the substance and all artifacts made from it were destroyed when Atlantis sank.
There are three schools of thought about orichalcum:
The Boring Theory
It never existed. It's just a word Plato used because it sounded cool.
The Metallurgic Theory
Orichalcum was an alloy of gold and copper or some other metals. There is a gold/copper alloy called tumbaga which was used by the ancient Incas and which bears a strong resemblance to Plato's description of orichalcum. Other suggested candidates are an alloy of gold and silver; chalcopyrite (a sulfide mineral); or brass (which was not that uncommon in Plato's day; nothing exotic about it). Some scholars have speculated that it might have been amber.
The Weirdness Theory
Orichalcum was a sort of Ur-Phlebotium with magical and/or super-science properties. In the Shadowrun universe, it is an arcane alloy which can only be made through alchemy and which cannot exist without the presence of magic. In some GURPS suppliments it looks like bronze, but it much harder and can be made into blades of remarkable sharpness. And in one old Indiana Jones computer game, it is a power source coveted by the Nazis.
Game and Story Use
- Any campaign involving Atlantis has to work orichalcum in there someplace. It's a rule
- An ancient artifact might be made out of orichalcum, whether it is of Atlantean origin or not
- If orichalcum is a power source, it would make a spiffy MacGuffin