Bentonite Powder

The different types of bentonite are each named after the respective dominant  element, such as potassium(K), sodium (Na), calcium(Ca), and aluminium (Al). Experts debate a number of nomenclatorial problems with the classification of bentonite clays. Bentonite usually forms from weathering of volcanic ash  most often in the presence of water. However, the term bentonite, as well as a similar clay called  tonstein, has been used to describe clay beds of uncertain origin. For industrial purposes, two main classes of bentonite exist: sodium and calcium bentonite. In stratigraphy and  tephrochronology, completely devitrified(weathered volcanic glass) ash-fall beds are commonly referred to as K-bentonites when the dominant clay species is illite. Other common clay species that are sometimes dominant are montmorillonite and Kaolinite. Kaolinite-dominated clays are commonly referred to as tonsteins and are typically associated with coal.