Most moai are made of tuff. Tuff is a soft volcanic rock native to Easter Island. (A few moai were carved from basalt and scoria, other volcanic rocks.) Because tuff erodes easily, few of the moai's original designs remain. Moai that were buried retain some original markings, which are similar to Rapa Nui tattoos of the period. https://www.nationalgeographic.org/media/quarry-easter-island/
It was Plato who said, “He, O men, is the wisest, who like Socrates, knows that his wisdom is in truth worth nothing”