Smectite
Synonym: Montmorillonite-saponite group; Swelling clay minerals; Expandableclay minerals.
Clades: Phyllosilicates.
Chemical: A0.3D2-3[T4O10]Z2 · nH2O
Mineralogy
Smectite is divided into subgroups that are:
- saponite, trioctahedral.
- montmorillonite, dioctahedral.
Smectite minerals have large specific surface areas and exhibit a high expansion capability in the presence of water.
Smectite is commonly a primary constituent of bentonite and pelitic sediments.
Smectites are monoclinic clay-like minerals.
The most common members are montmorillonite, nontronite and saponite.