Energy needed to turn granite to ashes

[Lightbuster30]

I know that the energy too vaporize stone is 25.7 kilojoules but what if there is ash markings? Like you make a crater and there is a black singe around the edges (no sign of rubble within the crater). Would it be safe to assume vaporization since the singe mark is an indication of heat? If not then what?

 

[Antoniofer]

Really if that I'm not sure if it is possible to turn granite into ashes via high temperature, they either tunrs into magma/lave or similar or into gas.

 

[Lightbuster30]

Well the only ashes are a small black burn mark around the crater, none inside the crater. And there was minor smoke (not dust, smoke) coming off of the crater. Would vaporization be a safe assumption in these cases