I don’t know what this stone really is or it’s lore. But I have an interesting fact for you. In the german version of the game DR is called “Götterfels”, you can translate it into “rock of the gods” or something similar. So maybe the name comes from this stone and the devs have more lore about the city than we know, e.g. the rock has a connection to the power of the six… something like this.
…or it is a really bad translation from the english name 