Mica powders are basically strongly pigmented, very fine, mineral powders. A little goes a very long way and if you use them more than very occasionally, do it somewhere with good ventilation (not a draft mind you) or with a dust mask because finely ground particles aren’t good to breath in.
That said, the sparkly, fabulous shades of mica powders are great for all sorts of surface decorations and even in colouring translucent clays to make lovely marbles. Check out this helpful video by Artesania Para Todos.
Is IT possible tot use the mica powder in porcelain clay