See hydrotalcite group.

a) occurs when a molecule reacts with water to break a chemical bond, and thereby often incorporating H₂O into the substance.

b) Hydrolysis at a surface involves the breakdown of the H₂O molecule into hydroxides and protons to form protonated/deprotonated surface sites.

A device used to measure the specific gravity of a fluid, usually containing suspended particles. In soil analysis, a hydrometer is used to measure the particle size distribution of fine-grained (< 75 μm) soils such as clays, on the basis of the Stokes’ Law: the settling velocity of suspended particles depends upon the particle size. With a time sequence of measurements of the suspension density, the quantity of particles settling out of the suspension can be estimated, and hence the size – quantity relationship (or particle size distribution) of different particles can be obtained.

An obsolete term for interlayer-deficient micas.

An obsolete term for illite.

An obsolete term for brammallite.

Surfaces or molecules with strong attraction for H₂O. Hydrophilic solutes are polarizable and tend to dissolve more readily in water than in oil.
Cf., hydrophobic

A poorly defined material, possibly interstratified phlogopite and vermiculite.

Hydrophobic materials, either surfaces or molecules, have little or no affinity for H₂O.
Cf., hydrophilic

A poorly defined material, possibly altered lepidolite.