A needle-like clay mineral composed of magnesium-aluminum silicate. Major deposits occur naturally in Georgia, USA. Attapulgite and sepiolite have similar structures and both can be used in saltwater mud to provide low-shear rate viscosity for lifting cuttings out of the annulus and for barite suspension. Attapulgite and sepiolite are sometimes called "salt gel. " Attapulgite has no capability to control the filtration properties of the mud. For use as an oil mud additive, the clay is coated with quaternary amine, which makes it oil-dispersible and provides gel structure but does not improve the filter cake, unlike organophilic bentonite clay.