i have two guild tab full of pyrite but i am still thinking every day that i should get rid of it. I'ts too easy, i really dont think blizzard will do something to easy for us.
They will bing a new ore, **truegold ore** wich will give the epic gem. Anyway i wont stack more than my 2 guild tab.
Quite honestly there are only 4 ways they can do Epic gems.
1) Pyrite Ore
2) Trash drops from that raid tier like Black Temple.
3) A new ore is introduced, which has never been done. Keep in mind this is the third expansion in a row that only had 3 different ores. Also if they were to do this, they would have to introduce an entirely new zone that would have it. While we have confirmed we're getting a new daily quest hub in Firelands, I can't imagine they would force us to old content to farm it, and the amount of griefing and competition would be enormous.
4) Last option is Epic gems are exclusively bought with Justice Points. They've already shown us they want items easily available via JPs, as it continues to give us outlets to spend them on.
I personally think epic gems will come from Pyrite and JPs in the same patch.