What exactly is clay?
Clay is a term used to describe a group of hydrous aluminum
phyllosilicate (phyllosilicates being a subgroup of silicate
minerals) minerals , that are typically less than 2 μm
(micrometres) in diameter. Clay consists of a variety of
phyllosilicate minerals rich in silicon and aluminum oxides and
hydroxides which include variable amounts of structural water.
Clays are generally formed by the chemical weathering of
silicate-bearing rocks by carbonic acid but some are formed by
hydrothermal activity. Clays are distinguished from other small
particles present in soils such as silt by their small size, flake
or layered shape, affinity for water and tendency toward high