I haven't tried Prep and Prime Face under my mineral makeup, but when I use mineral foundations, I do use the Smashbox primer underneath them. Bare Minerals has a tendency to make my pores ginormous, and the primer helps, but I find it to be by no means a miracle in preventing the pore appearance explosion! It does help the foundation to go on more smoothly and blend better, but alas, the huge pore problem remains!