Red platinum is the rarest metal the Adron houses draw from the eastern ranges, and they hold nearly all that exists. It is a platinum-group element that takes a red cast, recovered in trace amounts from the same Gozwin and Majesty peaks that give the kingdom its red gold, found beside the gold, a hundred times scarcer than it and rarer than common platinum by a wide margin.
What sets it apart from red gold is what it will not do. Red gold turns aside elemental Kethic, scattering a working of fire off its face. Red platinum turns nothing. A Kethic working brought against it passes clean through, and that absence is the whole of its worth as money. The counterfeit test runs on the inversion. A forged Crimson Crown struck in red gold throws a Kethic test off its surface; a true one struck in red platinum lets it pass. A coin that should be the most valuable object in the room and refuses to turn a flame is the genuine article.
The coin is the Crimson Crown, the highest face on the iron ladder, one rung above the Crown and barely a coin at all. It is worth more than ten thousand iron at no fixed multiple, since so few exist that each trades like a small kingdom changing hands. Most are never spent but sit vaulted in the time-frozen Bank of Infindior beside the titan-bone reserves, and they surface to settle the kind of balance that ends a war or buys a throne.