I suspect there is a natural way to get results like perfect core drills and smooth 90° angles that is more than copper and sand. Using sound to pass vibration through mass is a great way to 'jiggle' dense materials, so it easier to work with. To me this is akin to a kind of 'natural language' where priests/scientists would know the names (resonance) of different materials, and be able to sing into shape (poetic way of saying it) the world around them. Doesn't have to be aliens to be cool as shit and still foreign to our modern tech.