so i had a dream where a group and i were magically summoning like, liquid stone and by-hand forming it into walls--this is clearly half-baked and inefficient--so how would YOU make or enhance construction processes using magic, sci-fi technology, or fictional materials?
No it's great! Lava hardens into rock, so if you shape/form/mould it when it is lava, then it solidifies into the shape you want.
There are lots of ways of making things that rely on the thermoplastic effect: you shape it when it's liquid, then it hardens and you're done.
If the wizard could bend/conjure lava into any shape, he would be a useful man to have on your construction crew.