It seems you’ve deduced inferred a lot of the story so far!
You are correct, the resource they are after is indeed Anachronium. Dronghur is rich in the same, and that’s the reason so many primordial stones keep floating in its air space. ( I will not say more for the fear of spoiling. )
I’ve read this comment multiple times and it’s quite useful to me. The next draft will take all these points into consideration.