A British term for underclay.
Cf., underclay

A rock or sedimentary layer underlying a coal bed with physical characteristics suggesting that it served as a soil which supported the vegetation that produced the coal. (Modified from Huddle and Patterson, 1961)

Crystal growth from nanoparticles to larger particles that occurs by an assembly of aggregates, sometimes known as “oriented attachment”.

A mineral formed by an alteration process; the chemical constituents of a secondary mineral may be derived from the decomposition of a primary mineral and/or derived from outside the system during the alteration process.
Cf., primary mineral

In civil engineering, a clayey soil formed by transport and sedimentation of particles by water, air, or ice. Loess is an example of a sedimentary soil because it forms via wind transport and sedimentation. Sedimentary marine clay forms by deposition of fine-grained particles through seawater.

See pyrometric cone.

See astrophyllite group.

An obsolete term for celadonite.

An organoclay + organic solvent with an optimum gel strength that has not been augmented by additives, such as polar molecules (e.g., ethyl alcohol, acetone, propylene carbonate).
See gel strength, organoclay

Self-dispersing organoclays are clays that have additives to develop viscosity at much lower shear and energy input than other, non self-dispersing organoclays. An example of additives to form an appropriate complex are EDTA(ethylenediaminetetraacetic acid) and dimethyldihydrgenated tallow quaternary ammonium. This molecule intercalates into the organoclay and props the interlayer open to allow exfoliation.