I don't know anything about rocks, but it's very hard for me to take this website seriously when their FAQ repeats several times word for word (https://i.imgur.com/B0VojAZ.png):

>If it is not convincing enough: Recent scientific studies using very powerful and modern equipment found the ultimate evidence that the pyramids stones are synthetic. Believing in the artificial stone theory, or countering it, is simply no longer relevant. It has become a fact, a truth.

https://www.geopolymer.org/faq/faq-for-artificial-stone-supp...

In my experience, people who use repetition like this are not to be taken very seriously. It's a blunt persuasion tactic employed by the likes of used car salesmen and cult leaders.