Orichalcum Ore

Orichalcum Ore is a new Hardmode Ore that was introduced in the 1.2 patch.

If a player destroys a Demon Altar or Crimson Altar with a Pwnhammer after defeating the Wall of Flesh the world will generate either Orichalcum Ore or Mythril Ore, alongside with the other Hardmode Ores like Palladium Ore or Cobalt Ore and Titanium Ore or Adamantite Ore.

Trivia

 * Orichalcum is named for the fictional metal described by "Plato" in his work  "Critias", where it is mined only in the legendary lost city of "Atlantis".