"What about the Cheops pyramid? ...We have the core, this is the mass, more than 2 million tons ...made of ...reagglomerated limestone. But ...in the ...inner ...it is made of granite ...carved stone. Why? Cheops... is Khnum Kufu... agglomerated stone. However, Pharaoh is the king of the two countries. ...[T]he pyramids must be the representation of Egypt,... which means ...the replication of agglomerated stone for the northern part ....and in the south, natural granite that is the carving technology. So we have agglomerated limestone for the core, and the King's chamber is made of split granite that is dressed [cut] ...not carved granite."
January 1, 1970
https://en.wikiquote.org/wiki/Joseph_Davidovits