I think the stone maze is open to anyone. No key required. The portal is in BM where a few crids are. I'll save you some time. DON'T use ean. Unless you mean a skoid scroll and you have a good set of armor, a lot of pots, and a crazy sense of navigation. The passages are just barely wide enough for a jouster to fit through. So you shouldn't have much of a problem getting past ashcerions. Once you get down the stairs that goes to where the gem chest is, there are elite shockions, a few pidions, and, I've heard, a grision around there. Good luck with that.
