Bentonite is a clay material that is formed due to the weathering of volcanic ash. It is a type of absorbent clay that is commonly used in various industries such as construction, drilling, and agriculture. The process of formation of bentonite involves the following steps:

Weathering of Volcanic Ash:
When a volcano erupts, it releases a large amount of ash into the atmosphere. This ash settles on the ground and undergoes a process of weathering due to exposure to air and water.

Formation of Smectite Clay:
During the weathering process, the volcanic ash undergoes a chemical reaction in which the minerals in the ash react with water to form a type of clay called smectite clay. This clay is made up of tiny particles that can absorb water and other liquids.

Swelling of Smectite Clay:
When water is added to smectite clay, it causes the clay particles to swell and form a gel-like substance. This property of smectite clay makes it an ideal material for various applications such as drilling muds, sealants, and absorbents.

Drying and Processing:
After the smectite clay has been formed, it is dried and processed to remove any impurities and to improve its properties. The processed bentonite is then packaged and sold to various industries.

Conclusion:
In conclusion, bentonite is a material that is formed due to the weathering of volcanic ash. It is a type of absorbent clay that is commonly used in various industries such as construction, drilling, and agriculture. The process of formation of bentonite involves the weathering of volcanic ash, formation of smectite clay, swelling of smectite clay, and drying and processing of the clay.