Last crystal doesn't exist?

[FREAKE]

Okay so I love this game it's gorgeous and has got beautiful concepts so I decided I wanted to get 100% on the crystals, I have collected 74/75... but I have spent hours trying to find this last one and it's nowhere. It's in Snake Shore (listed on the EA guide), where I've got 5/6, but I've followed the guide and videos for all six of them and of course I don't remember exactly when I collected each crystal but every time I go to their exact location, there's nothing there. It would seem I have collected all six... but I'm still stuck at 74/75... Help? (Also this does include the crystal you find during the end credits)

[Xacarith]

I may know where it is though you should be able to locate it with the one skill. There is a place I don't think you can get back to after a point with out flying. It is glitch though. But I could be wrong about which one you're missing. The one I'm thinking of is in that area but way up on a cliff.