Hi, and thanks for the feedback. Based on yours and some other feedback I'm going to prioritize a feature for each mod that would allow disabling specific recipe modifications, to allow a much higher degree of customization.
Now, as for zircon in early recipes, there are two reasons I added it there:
- First, thematically, zircon is a good "refractory" material, so it really makes sense to use it in the early furnaces. In fact, zircon is commonly used to make refractory bricks, so I set that up in K2, where furnaces can take more than 1 ingredient. Perhaps a 50/50 split between "stone" and "zircon" would be more straightforward, though....
- Secondly, I wanted this mod to be involved a little bit at every stage of the game -- zircon early, zirconia and zirconium after green science, and then cermet as the advanced material.
Zirconium is used in explosives as a primer (which it can do in powder form, but I didn't want to add a powder form to the mod just for explosives recipe)
And in terms of zirconia+metal, that's basically what the cermet intermediate in this mod is meant to represent. There are many different combinations of ceramic and metal (cermet). This mod sort of simplifies them. A cool thing is that various cermet materials can be used for mechanical purposes or electronic purposes -- hence the variation in advanced things it goes into.
I'll keep your ideas in mind when designing the carbon mod, which is still being planned out.