Montmorillonite is a type of clay mineral that belongs to the smectite group. It is primarily composed of aluminum silicate and is known for its ability to absorb water and expand significantly when wet. This property makes it useful in various applications, including drilling fluids, cat litter, and as a thickening agent in products like paints and cosmetics. This mineral is named after the town of Montmorillon in France, where it was first identified. Montmorillonite is also used in agriculture to improve soil quality and retain moisture, making it beneficial for crop production. Its unique characteristics make it an important material in both industrial and environmental contexts.