So yesterday while working on my massive list of Cataclysm wonders, I got to get a little upcloseandpersonal with many of the new trainer-learned recipes and profession products. Something that really stood out to me was the Alchemy: Transmute Truegold recipe. It appears that Alchemists are the only profession masters that can produce this hot little bar that is used in both Blacksmithing and Engineering recipes to create new Heroic-dungeon level BoE epics.
The recipe requires:
3x Pyrium Bar
10x Volatile Fire
10x Volatile Air
10x Volatile Water
Pyrium Bar is attainable two ways:
Mining: Smelt Pyrite Requiring 2x Pyrite Ore
Alchemy: Transmute Pyrium Bar Requiring 4x Elementium Bar and 4x Volatile Earth
The rarity of these materials will heavily influence the price, as well as Alchemy transmutation cooldowns. I would assume that the mining route to Pyrium Bar would be the best bet, and will influence the price of the Truegold Bar. But ultimately, it's going to be the Alchemists deciding the price for the Truegold bars.