It seems I lost the dodecahedron for some reason. No idea what happened to it. I have already learned the language and got the bloody handkerchief, but I still need the dodecahedron journal. I have went back and checked and it's not where I took it. It is nowhere in my inventory or my companions inventory.

Well, oh and pardon me if I'm wrong Im only playing the game for the first time, you dont actually need the dodecahedron to get to Ravel's Maze. All you need now is the unfolding portal. I think to get that you have to get your legacy from the advocate in the Clerk's Ward, then you turn your Godsman receipt into the Godsman. Again I could be wrong.