Agree with the others; powerful mundane substances (including components) are the best use for this. But if I were the DM, I'd require a knowledge check to get the elemental composition right (easy for wood or stone, very difficult for unusual chemicals).
A single caltrop, instantly spotted because it's glowing with light.Conjure caltrops.
Aaaand the trifecta! Zero for three on reading the description.Conjure poison inside someone's muffin.