An older term for a variety of sepiolite often used to make pipes. Some meerschaum samples may contain amorphous material of similar composition to sepiolite.
Cf., sepiolite

See hydrotalcite group.

A poorly defined material, possibly biotite, stilpnomelane, or cronstedtite.

An obsolete term used for an iron chlorite.

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.

See thermally activated clay.

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

See tobermorite.