I have been researching this topic for sometime as I have a keen interest in studying ancient technology and attempting to find ancient technology in what has been discovered but misunderstood.
First a primer of a certain principle of quartz that not many may know. Quartz is a piezoelectric material often used today in circuit applications for maintaining frequencies, turning current into vibrations, and other applications. Most common would be piezoelectric buzzers and ultrasound.
This works because of crystal structure of quartz. When you compress quartz it creates a charge, when you stretch quartz it creates a opposite charge. This also works in reverse! If you apply a charge the quartz will react with mechanical motion, if you apply an alternating current it will vibrate. The quartz crystal has no limitation to how many times it can do this.
The one limitation comes in the form of an avoided phenomenon in modern circuits called Crystal Overdrive. Crystal overdrive is where you push a crystal with a resonant frequency that compounds its own mechanical motion. This creates distortion at its lower levels, but with too much power will result in the destruction of the quartz based on mechanical fatigue, causing the quartz to break.
In the famous words of Monte Python "get on with it"
Now we come to the point. Every monolithic site without fail is made from a stone that contains quartz. This is true of the Americas, Egypt, Europe, Asia, India, and other sites where monolithic sites exists with large construction and precise stone cutting and carving.
The hypothesis is that this principle of Crystal Overdrive is being used to cause localized destruction of quartz in stone resulting in the none quartz material to fall away not having the crystalline structure of quartz to hold the composite material as it is. Granite would yield silica sand, mica, and feldspar with other trace elements.
In regards to the power source for accomplishing this, I will have to quickly sum up another hypothesis I have been researching, which is the mastery of Electrostatics. This in of itself is something I have detailed out, but suffice it to say this is based on the simple premise of collecting charge slowly from structures that utilizes a slow charge from Atmospheric Electricity. A technology that the Egyptians did not invent, but copied from the older Sumerian culture. The origin before that I do not know.
Utilizing a static discharge of the right voltage would create a DC pulse discharge that can be applied at the resonant frequency of the quartz grains breaking them in a single pulse.
This theory would also satisfy the lack of advanced machinery and the fact only bronze tools have been found. This hypothesis would place these bronze tools and toothless "saws" as electrodes in a process of crystal overdrive to quickly erode stone works.
Let me know what you guys thoughts are as I am actively working on duplicating the process which I hope to have on video this week. Its been quite the hassle for me getting the equipment together for the experiment.