A group of hydrous silicates formed by weathering of minerals such as feldspar, pyroxene, or amphibole. Silicate tetrahedra are arranged in sheets.
Layered, platy minerals composed of hydrous aluminum silicates. Examples include kaolinite and chlorite
A group of very fine-grained minerals (alumino-silicates) which are the main constituents of clay. They occur as minute platelets which, when wet, slide across one another, giving the clay its plastic properties.
Alumino-silicate group of minerals, common in sedimentary rocks.
Those constituents of a clay which give it its plastic properties. An important characteristic is their ability to lose or take up water according to the temperature and amount of water present in the system. Clay minerals are produced by the degradation (weathering) of other silicates or silicate glasses. Five clay mineral groups are recognized 1. Kaolinite, 2. Illite, 3. Montmorillonite, 4. Vermiculite and 5. Palygorskite.
Fine, crystalline, hydrous silicates which form as a result of the weathering and decomposition of such silicate minerals as feldspar, pyroxene, and amphibole.
Clay minerals are hydrous aluminium phyllosilicates, sometimes with variable amounts of iron, magnesium, alkali metals, alkaline earths and other cations. Clays have structures similar to the micas and therefore form flat hexagonal sheets. Clay minerals are common weathering products (including weathering of feldspar) and low temperature hydrothermal alteration products.