Is it known exactly where the stone is going to be, or is it more ambiguous where the stone is? In other words, do we know roughly/exactly where it is we're going in the tunnels to find the stone? (Especially since I'm guessing the stone isn't directly visible from ground level seeing how it's in a pool of stuff.)

I'm curious exactly what context I should use to start a thread that would ultimately reveal the location of the stone.