Utterly Mad

Well, I am officially stumped. Chert is a sedimentary rock, and given a max edge in-between all the stone templates and obsidian. Diorite, gabbro, and granite are all igneous intrusive stones with no obvious interesting properties. Marble, quartzite, and slate are all metamorphic, and marble is the classic example of a stone that is non-economic in vanilla despite having use as flux.

Of those stones chert, gabbro, and quartzite are magma-safe. All of them are layer stones, not minerals.

So I have no idea what properties might've made these specific stones available for building despite currently being just as usable in stone tools. :V

EDIT: Wait, didn't you say the list of enabled stones was different? Someone said that it might be determined at embark.