Mineral composed with materials such as montmorillonite minerals of mica typed layer silicate, mineral among the Smectite groups, kaoin, quartz, cristobalite, mica, illite, etc.
The characteristics of bentonite

Swelling :
Expands 30~40 times its original size by absorbing moist between the layers of montmorillonite.

Cation-exchange-capacity :
Cations exist between montmorillonite layers, and the exchange amounts of cations are 90 ~ 120.

Colloid properties :
The size of a montmorillonite particle is 100~1000nm in diameter and 5~10nm in thickness. It has a similar size with a colloid.

Large surface areas :
Montmorillonite is composed with colloid-sized particles, and the theoretical inner surface area is 750~800m2/g.