K2's Welcome to Jungle technology unlocks crafting surface decorative entities like trees and rocks.
This can be used to convert stones into zircon ores via crafting Big/Huge Rocks. Is this intended?
I don't think it as a loophole though, because the whole process can not be automated.

K2 is one big beautiful loophole: endless fuel from atmosphere, endless wood, raw matter conversions and many more. Synthetic rock probably won't be the biggest issue.

Thanks for pointing this out. It's not explicitly intended. I agree it's not a major balance issue though. Thematically, do you think I should update the decoratives to require zircon in addition to stone?

As garrotte points, K2 already can create things from nothing so I think you can leave rock's ingredient as it is.

I would like to add that this issue also exists with the rocks added by Dectorio, and that is an undesired loophole.

Thanks! The Dectorio one seemed like more of a loophole due to the price of the recipes, so I went and fixed it for both Dectorio and K2 since I was going in anyways.