Bentos
is an absorbent aluminum phyllosilicate, impure clay consisting mostly of montmorillonite. The absorbent clay was given the name betonies by Wilbur C. Knight. There are different types of betonies, each named after the respective dominant element, such as potassium, sodium, calcium and aluminum Experts debate a number of nomenclatorial problems with the classification of betonies clays. Betonies usually form from weathering of volcanic ash, most often in the presence of water
Types
Two main classes of betonies exist: sodium and calcium betonies. In stratigraphy and tephrochronology, completely devitrified (weathered volcanic glass) ash-fall beds are commonly referred to as K-betonies when the dominant clay species is illite. Other common clay species, and sometimes dominant, are montmorillonite and kaolinite. Kaolinite-dominated clays are commonly referred to as tonsteins and are typically associated with coal
Uses
The main uses of betonies are
Drilling mud
Binder
Purification
Absorbent
Groundwater barrier
Medical
In Thai farming