It's Tarte Cosmetics' Smooth Operator Micronized Clay Finishing Powder. It not only sets your makeup, it also hydrates your skin and absorbs oil. The powder also reduces the appearance and size of pores by 20% which I think a lot of people like. It's also talc-free, so you won't get that white cast that some, if not most, finishing powders give. The powder contains Amazonian clay, which I believe, is a gift from God. It really keeps your skin hydrating and looking young. It also keeps your skin from drying out and flaking.
I honestly LOVE this product. I use it on my eyeliner and it keeps it from smudging. I've finally found my HG finishing powder. I included a review video below.
If you end up trying the product, let me know what your take on it is =)