Bentonite

Bentonite is a kind of clay.  Bentonite usually forms from weathering of volcanic ash. It is volcanic ash mixed with water under  pressure.

The different types of bentonite have different proportions of sodium, calcium or potassium. They can absorb quite a lot of water, and are used as fillers and/or lubricators in various industries. The clay is used for many practical purposes.

Category:Sedimentary rocks
Category:Sodium compounds
Category:Calcium compounds
Category:Potassium compounds
Category:Natural materials