Fuller’s earth is a clay-rich material used mainly as a cleaner and purifier. The material consists mostly of hydrated aluminum silicates–minerals made up of water and compounds of silicon, oxygen, and aluminum. Often, the material is also rich in compounds of calcium and magnesium. The surface of fuller’s earth attracts greasy and oily substances. Factory workers use fuller’s earth to soak up oil that has spilled on the floor. Used in litter boxes, fuller’s earth soaks up animal wastes. Petroleum companies use it to purify and lighten the color of crude oil.
Fuller’s earth also acts as a catalyst, a substance that increases the speed of a chemical reaction without being consumed. People once used a form of fuller’s earth to remove grease from cloth and wool. Fuller’s earth gets its name from this process, called fulling.
