So, time to doublepost because no one ever uses this thread.
Regarding Kobold Kamp, I'm thinking about making it so only certain stones are sharp enough to be used in weaponry. This would avoid the extremely haphazard way the game enables certain stones for building. It would also increase the difficulty by making usable sharp stone less available.
There is a catch though. I've been populating a list of logical stones to use based off of attempts to find historical use in knapping, as well as properties that MIGHT make an ahistorical stone suitable (like ilmenite). But so far, chert is the only sedimentary stone on that list, none of the igneous intrusive stones would make sense for that, and all the other logical choices are igneous extrusive or metamorphic.