I read something similar in Omni magazine a long time ago. The article I read “claimed” that the granite in the Pyramids is consistent with what a granite concrete would look like. It would be easier to transport ground-up granite which is “formed” the same way we build concrete buildings.
Not saying it is true considering the source but it is a reasonable theory.
The Omni article probably was about Davidovits, I wonder if it was in the Antimatter? I believe those are archived online.