An entity, either a solid or a liquid, dispersed in a medium. The entity must have one of its dimensions between 1 nm and 1 μm. A colloid dispersed in a liquid is also termed a “sol”. The term may be used also for the system as a whole. (after Lyklema 1991).
See gelling clay.

See suspension.

See suspension.

An obsolete term for roscoelite.

The relationship where a superstructure (or superlattice) is equal to an integral number of subcells (or sublattices). For example, some crystals of antigorite exist where the substructure a-cell dimension is 5.4 Å, and the superstructure of 32.4 Å, occurs from a wave-like curvature of the 1:1 along the [100] direction. Because the superstructure is 6 x 5.4 Å = 32.4 Å, the superstructure is commensurate with the substructure. In other crystals of antigorite, the superstructure may be related to the substructure by a non-integer number of subcells, and this is referred to as a non-commensurate relationship.

The relationship where a superstructure (or superlattice) is equal to an integral number of subcells (or sublattices). For example, some crystals of antigorite exist where the substructure a-cell dimension is 5.4 Å, and the superstructure of 32.4 Å (6 x 5.4 Å), occurs from a wave-like curvature of the 1:1 layers along the [100] direction. Because the superstructure is a multiple of the subcell dimension, the superstructure is commensurate with the substructure. In other crystals of antigorite, the superstructure may be related to the substructure by a non-integer number of subcells, and this is referred to as an incommensurate or non-commensurate relationship.

An obsolete term for muscovite.

See cryptocrystalline.

a) In geology, compaction (= geological compaction) refers to the densification process caused by the gradual increase of overburden (weight) resulting from continuous deposition of sediments or by pressures from the movement of rock within the crust.

b) The geologic process of changing fine-grained sediment to consolidated rock, as in clay to shale.

c) In soils engineering, compaction is the artificial process to improve the engineering properties of a clay or soil by mechanical energy (e.g., vibration, static pressure). The clay or soil is usually partially saturated and thus contains mineral particles, air, and water. Compaction reduces the volume of air in the pores so that the dry density of the soil/clay increases. In practice, to maximize compaction, the water content is adjusted to a suitable value, called the optimal water content, so that the dry density approaches a maximum value.
See water, optimal content for compaction; consolidation, clay or soil

A complex is a dissolved or surface species that forms by association of a cation and either an anion or a neutral molecule, the latter anion or molecule is often referred to as a ligand. The complex may have an overall charge that is positive, negative, or neutral.