According to Greene-Kelly (1953), Lim and Jackson (1986), and Volzone (1991), small ions in the interlayer position move into the vacant octahedral sites in dioctahedral
minerals after moderate heating.
Inhibited vermiculite is a common constituent of kaolinite-dominant soils and its occurrence could be attributed to alteration of dioctahedral
mica that persists in deeper horizons of these soils.
The Greene-Kelly (1953) test differentiates dioctahedral
smectites on the basis of the seat of layer charge.
Tsipursky SL, Drits VA (1984) The distribution of octahedral cations in the 2:1 layers of dioctahedral
smectites studied by oblique-texture electron diffraction.
The montmorillonite is composed of dioctahedral
smectites with predominantly octahedral substitution, while the saponite is composed of trioctahedral smectites with mainly isomorphous substitution of [Si.
The synthetic clay used for these studies was a dioctahedral
three-layer tetrasilisic fluoromica (SOMASIF MAE) produced by CO-OP Chemical Co.
In soils literature this mineral is referred to by a variety of names including dioctahedral
chlorite, chloritised vermiculite, and inhibited vermiculite (Norrish and Picketing 1983); in the present work we refer to this phase as pedogenic chlorite.
Surface formations around the pan basins of the southwestern Kalahari are Kalahari sands, whose clay fraction consists of muscovite and dioctahedral
smectite, at least in the Otjomongwa area (Mees 2001).
This is possibly because, in an oxidising environment, the octahedral Fe is oxidised and imparts to the mineral a dioctahedral
character, holding K more tenaciously (Rich 1972) because of short K-O distance and larger K H distance in dioctahedral
The dominant clay mineral was found to be dioctahedral
montmorillonite with minor amounts of illite and kaolinite.
While MMT is a 2:1 phyllosilicate, rectorite has a 1:1 type of layer structure arranged regularly with an alternating dioctahedral
mica layer and dioctahedral
Rich CI, Cook MG (1963) Formation of dioctahedral
vermiculite in Virginia soils.