The Smectite Group is a category of clay minerals known for their ability to expand and contract when they absorb water. These minerals are primarily composed of layered silicate structures, which allow them to hold water and other substances between their layers. Common members of this group include montmorillonite and bentonite, which are widely used in various industrial applications. Smectite minerals are important in fields such as geology, agriculture, and environmental science. Their unique properties make them useful for applications like drilling mud in oil extraction, cat litter, and as additives in ceramics and paints. Their ability to retain moisture also makes them beneficial for soil improvement.