What Are the Types of Bentonite Clay?

Bentonite clay, also known as the mineral montmorillonite, is common to volcanic ash and is a part of the smectite group of clay, which are groups of clays with three layers. Numerous types of bentonite clay exist, and while each type has properties that serve to set each clay apart from the other, the clay types all share the common characteristic of being able to absorb water at a significantly higher rate than other forms of clay.

Calcium Bentonite

• Calcium bentonite, known also as the "non-swelling" type of bentonite, possesses the same amount of minerals as other forms of bentonite clay but doesn't absorb as much as sodium bentonite. It is often sold as a fine powder and is commonly used as an absorbent clay for clean-ups or mixed with water and consumed as a part of a detoxification regimen suggested by alternative medicine enthusiasts.

Sodium Bentonite

• Also known as "Swelling Clay," sodium bentonite is capable of holding many times its weight in water. This capability makes it usable as a sealant for older, unused oil wells and toxic waste storage areas, as it bonds with the natural surrounding soil to create a barrier where oil and toxins cannot penetrate. It is not suitable for internal use due to its swelling capacity, and is used most often for industrial use.

Potassium Bentonite

• Potassium bentonite, known also as "potash bentonite," is an illitic clay with a high potassium content. Illitic clays are also considered non-swelling and are used to produce building materials such as bricks and molding sand, as well as radioactive waste containment.