A recrystallization process where the smallest crystals dissolve and the chemical constituents are added to the larger crystals of the same phase. This process of crystal growth and coarsening occurs in a solution. The driving mechanism is a shift to lower surface free energy (Ostwald, 1900 in Baronnet, 1982).

Defined by Schultz (1969) for montmorillonite samples [current nomenclature for montmorillonite is that it is an Al-rich, dioctahedral smectite with an ideal structural formula of (Al_3.15Mg_0.85)Si₈O₂₀(OH)₄X_0.85.nH₂O with layer charge from primarily octahedral substitutions of Mg] with a large net negative layer charge [-0.80 to -1.20 per unit cell, O₂₀(OH)₄] obtained almost entirely (<0.15 charge from tetrahedral sheet) from cation substitutions in the octahedral sheet, although exceptions were noted. This classification scheme was based on chemical and thermal analysis. The term is obsolete and should not be used. Terms used in this obsolete classification are: Wyoming-type, Otay-type, Chambers-type, Tatatila-type, beidellite-type (ideal and non-ideal), and non-ideal montmorillonite. See also Part 2 of the Glossary.

See Stern layer.

Ions adsorbing in the outer Helmholtz plane form outer sphere complexes. The larger distance to the surface relative to the shorter distances of inner sphere complexes may result from retaining H₂O molecules (via hydration) between the surface and the ion.

In mining, overburden refers to the unusable material(s) that is above the ore of interest. Overburden may be removed or left in place (by tunneling below it).

A process or phenomenon where a soil or clay mass has previously been subjected to pressures that were greater than the current overburden pressure.

In soil science and soils engineering, the overconsolidation ratio (OCR) is the ratio of the preconsolidation effective stress to the current consolidation effective stress to which the soil is being subjected. For normally consolidated sediment the OCR = 1.0, thus for overconsolidated sediment the OCR >1.0.

A poorly defined material, possibly an altered iron-rich chlorite, from near Harper’s Ferry, West Virginia, USA.

A member of the brittle mica group, with an ideal chemical composition of Ba(Mg₂Ti⁴⁺)Si₂Al₂O₁₂. Oxykinoshitalite is the Ti and oxygenian dominant analogue of kinoshitalite. Oxykinoshitalite-1M forms in the C2/m space group with Ti primarily in the M2 site. It occurs in an olivine nephelinite from Fernando de Noronha Island, Pernambuco, Brazil (Kogarko et al., 2005).