Bentonite is a very soft plastic clay consisting predominantly of montmorillonite, a fine particle-sized hydrous aluminum silicate and member of the smectite group. Most bentonites are formed by the alteration of volcanic ash and rocks after intense contact with water. Bentonite presents strong colloidal properties and increases its volume several times when coming into contact with water, creating a gelatinous and viscous substance. Its specific properties include swelling, water absorption, viscosity, and thixotropy. These properties are in demand in a huge range of industries served by Imerys, earning it the nickname ‘the mineral with a thousand uses’.

Bentonite is an aluminum phyllosilicate clay composed of montmorillonite with the chemical formula (Ca,Na)0,3(Al,Mg)2Si4O10(OH)2 ·n H2O.

Physical properties:

- Strong colloidal properties

- Swells in contact with water

- Water absorption

- High viscosity

- High plasticity

- Thixotropy