Bentonite

Bentonite clay goes by the same name on the label and off it: Bentonite. It's named after the Benton Shale in Wyoming, where it was first described. The Benton Shale was named after Fort Benton in Montana. Fort Benton was named after Senator Thomas Hart Benton. So this clay is named after a rock layer named after a fort named after a politician. Government names, all the way down.

Superhero or supervillain?

Superhero. Its superpower is swelling. Add water and it soaks it up and puffs up, which makes it one of the most absorbent clays around.

What it does in my skincare

In soap, bentonite adds slip, that smooth, slippery feel in the lather. It doesn't add much color, just a soft gray-cream. In a clay mask, it absorbs excess oil on the skin's surface. It's the strongest absorber of the clays, so a little goes a long way.

The supervillain rumor

Bentonite is often sold as a "detox" clay. What it really does on skin is absorb oil and hold on to dirt at the surface, which then rinses away. That's cleansing, not detoxing, and it's plenty.