Ancient pre-Inca temples - vitrified stonework - moulded rock walls... how how how?

Literally, "How do you sufficiently heat a rock such that it gains a molecularly-altered shiny patina without making the rest of the rock crack under the intense heat needed?"



Is this technique of moulded architectural details or bricks, tight internal angles and external skin vitrification evidence of some amazing lost art of the stone-mason?



Seriously, it's hard to work out whether these 'seemingly carved' globally-found stone items were moulded then vitrified or simply carved out of the native rock/marble with LASERS.