I'm turning it into truegold on my alchemists. Epic gems are at least a year off... and you'll have plenty of time to generate a full cache of it once they announce the epic gems (on the PTR). At that point you'll still have at least a month or more before the major content patch... and thats plenty of time to get a truckload of it.
---------- Post added 2011-02-02 at 04:40 AM ----------
While this seems to make good sense, it has some serious flaws. Such as that once epic gems are released... rare gems will be worth trash.... many already are.
Beyond that, on my server at least, its a huge loss to try prospecting pyrite. The only valuable uses I currently see for it are in making gear and/or truegold. The only thing propping its high price is its scarcity as its not valuable for most JCers currently.