An obsolete varietal term for biotite.

In clay science, mesopores (Figure 3) are cavities with diameters of 2 – 50 nm within a clay sample in accord with IUPAC convention (Rouquerol et al., 1994), although in soil science mesopores are defined as between 30 – 70 μm (Soil Science Society of America, 1997). In clays, these pores are present between mineral stacks of several unit structures. The pore volume (or pore size) distribution of clays is commonly determined by gas adsorption methods (typically H₂O or N₂).
Cf., macropore, micropore

A poorly defined material, possibly a weathering product of biotite.

Obsolete term for less hydrated form of halloysite, now halloysite (7 Å).

See tobermorite.

Kaolin material that has been heat-treated to partial or complete dehydroxylation.
Cf., dehydroxylate, dehydroxylation, thermally activated clay

An obsolete term for muscovite.

A poorly defined material, possibly interstratified phlogopite and vermiculite.

A general term for platy phyllosilicates of 2:1 layer and a layer charge of ~ -1.0 per formula unit (true mica group) or ~ -2.0 per formula unit (brittle mica group) or between -0.6 to -0.85 per formula unit (interlayer-cation-deficient mica group, abbreviated to interlayer-deficient micas). Micas do not show swelling capability. Octahedral character, either trioctahedral or dioctahedral, further divides the mica groups into subgroups, whereas chemical composition separates the species within the subgroups.
Cf., true mica, brittle mica, interlayer-deficient mica, group names

A mineral habit where individual grains are platy in shape, as often caused by a single plane of cleavage.
Cf., habit