Take the shield to Aydnn Peacemantle and have him test it’s resilience against the Obsidian Dust.
Even you shouldn’t be able to mess up this simple task. Take this shield to Peacemantle and see if the protection is good enough.
You have something you wish to discuss?
Well then, let us see how it stands up to this evil stuff… Ah, it seems to have failed. Hmmm, give me some time to think, and I’ll come up with a plan.