There are a few key differences between bentonite and clay. For one, bentonite is typically characterized by its high absorbency, whereas clay is not. This means that bentonite can swell up to 15 times its original size when exposed to water, whereas clay will only absorb a small amount of water. Additionally, bentonite has a much higher cation-exchange capacity than clay, meaning it can exchange positively-charged ions with the soil it comes into contact with. Finally, bentonite is also known for its binding properties, which clay does not have. All of these properties make bentonite ideal for use in things like drilling, construction, and even cosmetics.