A type of clay mineral (e.g., montmorillonite) that undergoes reversible expansion on absorbing water.
- ‘The clay mineral smectite, with physical properties that make it unsuitable as a soil if it is wet, is only found in major amounts in covered stadiums.’
- ‘Common clays are usually mixtures of clay minerals such as illite, smectite, and kaolinite, together with fine silica and other minor constituents.’
- ‘The clay is composed of illite and kaolinite, with minor amounts of chlorite and smectite.’
- ‘The limestone-dolomite breccia is characterized by abundant palygorskite, minor sepiolite, rare kaolinite and near absence of smectite.’
- ‘The lake may have dried up or nearly dried up periodically, producing outward concentric zones of albite, analcime, clinoptilolite, and smectite.’
Early 19th century: from Greek smēktis fuller's earth + -ite.