Fuller’s earth is any clay material that has the capability to decolorize oil or other liquids without chemical treatment.
Fuller’s earth consists primarily of hydrous aluminum silicates (clay minerals) of varying composition. Common components are montmorillonite, kaolinite and attapulgite. Small amounts of other minerals may be present in fuller’s earth deposits, including calcite, dolomite, and quartz.
Modern uses of fuller’s earth include absorbents for oil, grease, and animal waste (cat litter) and as a carrier for pesticides and fertilizers. Minor uses include filtering, clarifying, and decolorizing; active and inactive ingredient in beauty products; and as a filler in paint, plaster, adhesives, and pharmaceuticals.
Historically, textile workers, or “fullers” as they were once called, would clean raw wool by kneading it in a mixture of water and fine earth. The ‘earth’ consisted of a number of clays. This process cleaned the fibres by absorbing dirt, oil and other contaminants.