Now that is an technical sngle that I'd be really curious about. How is the energy footbrint of cutting and machining stones in comparison to pouring concrete? How for the whole of mining tarnsporting cutting stone in comparison to mining sand and lime, firing the concrete, transporting and pouring it? Would seem like the energy that is already invested through geological processes to make stone (sedimentary, metamorphic, pyrophoric) would be a huge share of the energy. The whole chemical energy needed for concrete should be huge comparatively to blasting once way through a rock deposit and cutting it. But then that is entirely unsubstantiated and I'm very aware that such intuited assumptions are very prone to erring.