Mica is a mineral powder made up of silicates. This material has several functions, where the main one is acting as a colorant in skincare products. It often features a shimmery appearance, making it highly desirable in certain cosmetic products.
Mica also serves as a slip modifier, meaning it causes the product to apply more smoothly and with higher spreadability. In addition, mica can act as an opacifying agent. This simply means that it can provide coverage, such as to blemishes or dark circles.
Within skincare products, mica is relatively safe. The largest safety concern with mica is respiratory irritation when a large amount is present in the air, such as in a manufacturing facility.