Crossword Genius

Created by volcanic activity, as rock (7)

Ross

I believe the answer is:

igneous

(Other definitions for igneous that I've seen before include "Originally molten (rock)" , "Of fire, like rocks formed from molten material" , "Formed of solidified magma" , "Fire-formed rock" , "produced by fire" .)

I've seen this clue in The Guardian.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.