Mica is a naturally occurring mineral dust. It's usually used as a filler but in Runpowder it's here to give a blemish-blurring, glow-boosting oomph!
If you've ever seen Mica on an ingredient watchlist, please know it's utterly safe and one of the very few cosmetic coloring agents approved by the FDA and even in food. The concern is re worker-safety in dusty mines.
Phyte Club sources mica from a supplier who actively addresses worker-safety and proactively ensures their lives and prospects are radically improved.
Extra-Credit! Read more about it.