An illite is a group of minerals close to clay containing silicates with aluminum and potassium insertions. One type of it was found and described in Illinois, thus got its name.
The sedimentary origin of this mineral allows making fine powder with hard particles for mechanical exfoliation, removing old, dull, or dead cells from the skin surface.
Illite is an excellent and safe adsorbent with high abundance and stability. This property allows using formulations to eliminate heavy metals like thallium, lead, six valent chromium, and others in cleansers, exfoliators, and clay masks.