Fuller's Earth - Occurrence and Composition

Occurrence and Composition

In 2005, the United States was the largest producer of fuller's earth with an almost 70% world share followed at a distance by Japan and Mexico.

Fuller's earth usually has a high magnesium oxide content. In the United States, two varieties of fuller's earth are mined, mainly in the southeastern states. These comprise the minerals montmorillonite or palygorskite (attapulgite) or a mixture of the two; some of the other minerals that may be present in fuller's earth deposits are calcite, dolomite, and quartz.

In England, fuller's earth occurs mainly in the Lower Greensand. It has also been mined in the Vale of White Horse, Oxfordshire, England. The Combe Hay Mine was a fuller's earth mine operating to the south of Bath, Somerset until 1979. Other sites south of Bath included Frome, Lonsdale, Englishcombe, Tucking Mill and Duncorn Hill. Although these sites had been used since Roman times William Smith developed new methods for the identification of deposits of Fuller's earth to the south of Bath. Other English sources include a mine near Redhill, Surrey (worked until 2000), and Woburn, Bedfordshire, where production ceased in 2004.

In some countries calcium bentonite is known as fuller's earth, a term that can also refer to attapulgite, a mineralogically distinct clay mineral that exhibits similar properties.

Hills, cliffs, and slopes that contain fuller's earth can be unstable, since this material can be thixotropic when saturated by heavy rainfall.