Saliotite is a regular interstratification (mixed layer) of cookeite-like and paragonite-like layers in a ratio of 1:1 (Goffé et al., 1994). The ideal chemical composition is Na_0.5Li_0.5Al₃(Si₃Al)O₁₀(OH)₅ and it occurs in high-pressure, low-temperature metamorphic rocks (estimated at 280-330^oC, 8 kbar) in Andalusia, Spain.
Cf., interstratification

An obsolete term for barian muscovite.

See alkali feldspar.

Saponite is ideally (M⁺_x–y ^. nH₂O)(Mg_3-yR³⁺_y )(Si_4-xAl_x)O₁₀(OH)₂ where M is the exchangeable cation in the interlayer (univalent example given here), R³⁺ are y trivalent cation substitutions in the octahedral site, x is the number of substitutions for Si by Al in the tetrahedral sites, and n is variable. Natural samples (Moore and Reynolds, 1997) may show < 0.66 Al tetrahedral atoms per asymmetric unit [O₁₀(OH)₂] to produce a large negative charge in the tetrahedral sheet which is balanced by positive charge in the octahedral sites (R³⁺ cations) and interlayer exchangeable (M) cations. Octahedral site vacancies may also occur (Newman and Brown, 1987). Suquet et al. (1975) determined that the two-layer hydrate structure (two planes of H₂O) of a Na-saturated sample is C centered with a = 5.333, b = 9.233, c = 15.42 Å, β = 96.66 ^o. The sample approximates a Ia-2 polytype. The d(001) values of saponite commonly range from 13.5 (air dry) to 16.8 Å (ethylene glycol treatment). Dehydrated K-exchanged saponite shows a mica-like structure with stacking described as either a 1M or 3T structure. Saponite with a Mg-rich octahedral sheet is usually, but not limited to, a weathering product involving volcanic rocks (see Guggenheim, 2011 for a literature review of natural and synthetic saponite). Ferrian saponite (e.g., Kodama et al., 1988) with a composition of (M⁺_0.61 ^. nH₂O) (Mg_1.39Fe³⁺_0.85Al_0.17Mn_0.03) (Si_3.49Al_0.51) O₁₀(OH)₂ and ferrosaponite (Chukanov et al., 2003), (Ca_0.31Na_0.04K_0.01 ^. 4H₂O) (Fe²⁺_1.54Mg_0.85Fe³⁺_0.45)_{Σ = 2.84} (Si_2.87Al_1.01Fe³⁺_0.12) O_9.67(OH)_2.33, occur in a gabbro saprolite and as a hydrothermal mineral in basaltic pillow lavas, respectively.
Cf., smectite

A residual, sedentary, in situ regolith developed by chemical weathering of rocks, most often primary crystalline (igneous and metamorphic) bedrock. Saprolite preserves parent-rock textures in the form of abundant, predominantly argillaceous, and commonly pseudomorphous weathering products of individual primary minerals. Preservation of parent-rock mineral textures and fabrics in saprolite is often associated with high microporosity and may be a consequence of isovolumetric weathering. Saprolites are typically some meters thick but can be hundreds of meters thick.

An obsolete term for illite.

The condition where the voids within a material are filled with water. The degree of water saturation is the ratio of pore water volume to the total pore volume, usually expressed as a percentage.

A measure of how far from equilibrium a solution is with respect to a given mineral. The saturation index, SI, is determined from SI = Q/K_eq, where Q is the reaction quotient and K_eq is the equilibrium constant, often given as log₁₀ (Q/K_eq). When SI = 0, then the system (water + mineral) is at equilibrium, if SI < 0, the mineral will dissolve, and if SI > 0, then the mineral will precipitate.

The Zn²⁺-rich trioctahedral smectite (Ross, 1946) with the ideal composition of (M⁺_x ^. nH₂O)Zn₃(Si_4-xAl_x)O₁₀(OH)₂ where M is the exchangeable cation in the interlayer (univalent example given here), x is the number of substitutions for Si by Al in the tetrahedral sites, and n is variable. Zn content may vary commonly from 1.48 to 2.89 atoms per O₁₀(OH)₂, and the octahedral site may contain vacancies. Mg, Fe³⁺, and Al are known to replace Zn (Faust, 1951).

An obsolete term for lepidolite.