This has been mentioned multiple times but I felt the need to give my take on it.
Reinforced stone is terribly balanced with it’s black ice counterpart. The main reason I say this is because of the time investment required for making the build pieces.
I’ll compare foundations for this exercise, using t3 thralls.
Black Ice needs:
5 Black Ice
4 Dry Wood
As base materials.
Reinforced Stone requires:
9 Plant Fiber
The ironstone turns into steel reinforcements in each case. Dry wood and resin turns into insulated wood, Ichor and plant fiber turn into stone consolidant, wood turns into shaped wood, stone turns into bricks and then hardened bricks.
The big difference is in the harvest times, and craft times at stations.
With black ice, every component can be crafted in parallel, no matter how you do it. Black ice is harvested hundreds at a time, in completed form. It’s only disadvantage is needing warm clothes and a trip up north, but you can return with hundreds to thousands of it, enough for hundreds of foundations. While this is happening, wood can be drying, while insulated wood is being made, while steel is being made, all in parallel.
With reinforced stone, I need the same station (furnace) for the iron and steel like black ice… but ALSO the bricks and hardened bricks. The firebowl needs to make steelfire… and ALSO stone consolidant. Meanwhile, the stone requirements for mining are 30 times higher than black ice.
This means it takes 30 times as many swings to get enough materials… and you can’t make the components in parallel, you must decide on iron or bricks, steel or hardened bricks, consolidant or steelfire, until you have enough. You also need ichor, which you need to gather fish for (broken right now) or actively kill spiders (only certain kinds) to get.
When we look at the process holistically, we can easily see that black ice can be made in mass quantities, much much faster than reinforced stone. Since they are otherwise equal, the best method for achieving T3 protection is always going to be black ice. It will happen fast every time, with less active harvesting required by the player, and less crafting time at the benches, by a HUGE margin.
I am not sure if you as the devs think about the balance, if either is too easy or too hard, but their crafting difficulty needs to be at least somewhat similar. Two choices when one is clearly highly inferior is not actually two choices. You could argue the materials for reinforced stone are easier to find, but at T3, going places is not an issue anymore.
My suggestion is to raise the black ice cost, and lower the reinforced stone costs to be more balanced. You could easily double the black ice requirements, and halve the hardened stone requirements, and you would begin to get into the realm of being comparable.
Edit: A different suggestion would also be to lower the craft times of bricks and hardened bricks.