From my understanding mica is considered very safe for use in cosmetics. Coloured mica, however, seems to be normal mica mixed with other colourants like iron oxides, dyes, or ultramarines. Ultramarines are not classified as safe for use on the lips, I believe, but some places that sell coloured mica don't list the ingredients. Is a mica that is mixed with a nonlip safe ingredient still safe for the lip? If yes, why?