I scrape together enough magic to create a grade 1 orange gem, sneak near the wall to place the gem nearby, and use it to drain the mana of the wall away, and into myself. It should do some damage as well. (displayed stats: 9-12 damage/shot, 50 firerate+/-). The gem will deteriorate quickly, as it's not in a tower.
I go back to my smithery, forge a sword made out of Lonsdaleite (58% harder than diamond, the hardest thing in the world) and attack the mortar between the bricks with it.