As ryan said when we change over to 1.6 there will be a reset. But I would like to point out that there is still plenty of quartz in there. You just have to go deeper into the nether is all.
Hmm, I have one into the nether myself recently and while there is some quartz deep in the nether much of it is gone. Nether afk is mined insanely fast w an eff 5 pick so the nether is practically destroyed.