A naturally occurring clay material (chiefly montmorillonite) that has the property of decolorizing oil and grease. In the past raw wool was cleaned of grease and whitened by kneading it in water with fuller’s earth; a process known as fulling. Fuller’s earth is now widely used to decolorize fats and oils and also as an insecticide carrier and drilling mud. The largest deposits occur in the USA, UK, and Japan.
Geology and Earth Sciences
1. A clay consisting mainly of expanding smectites such as montmorillonite used industrially for its absorptive properties.
2. Capitalized, Fuller’s Earth is the stratigraphic name of a Jurassic clay formation outcropping in southern Britain.