Lithium Extractor & other questions

[jhlee01]

So i've been playing with a group of friends and we are trying to figure out how a few things work.

I know the giant blue crystals can be harvested but outside that there are giant brown stones. What are these for? I can't really seem to do anything with them.

How do i build lithium/OIl Rigs? Do i build the rigs over a specific resource or just throw it down?

[Lurler]

there are giant brown stones. What are these for? I can't really seem to do anything with them.

These are purely decorative.

How do i build lithium/OIl Rigs? Do i build the rigs over a specific resource or just throw it down?

You need to unlock xenogeology first. And yes, you need to build them over their respective resources as per their description.