But, if you can understand how tufa is formed, you may get some idea of how they occurred. Each locality has different variations of stone, even igneous ones. And the erosion factors differ all over the planet, so what you see in one place may not be identical with somewhere else.
Giza seems to be Ground Zero for stonework, however, because that landscape is now desert, understanding underlying processes can be difficult when the mechanisms for creating lithification no longer exist.
None of these pillow, randomly patterned, close fitting, sometimes bonded stones were created by simply chemical means. Yes, precipitation is a chemical process, but it needs an original host for its formation - just as a pearl needs a grain of sand.
The bosses have nothing to do with lifting or whatever.
There are even reverse bosses.
The answer is there. But you will need to take off your 21st C glasses first.
I'm not saying anymore about this on this forum.