A construction material (usually red, yellow, or pastel in color, generally rectangular in shape) mainly composed of calcium silicate phases, after firing or drying clay. Recycled and milled bricks (brick-dust) are used as additives in the production of lime mortar.
A platy serpentine with an ideal composition of (Ni1.75Al1.0)(Si1.5Al0.5)O5(OH)4. Crystals are generally poorly crystalline mixtures of hexagonal and monoclinic polytypes. Poorly described, Al-rich material similar to a Ni analogue of amesite (referred to as “nimesite”) was redefined as brindleyite. Brindleyite is compositionally similar to berthierine because of the tetrahedral Si/Al ratio and structurally similar owing to the hexagonal and monoclinic polytype intergrowths. Brindleyite has been found in the Marmara bauxite deposit, Greece.
Cf., amesite, berthierine, garnierite, nepouite, pecoraite, pimelite, willemseite
A regularly ordered interstratification of a pyrophyllite-like layer and dioctahedral smectite-like layer in a ratio of 1:1 (Dong et al., 2002)
Cf., interstratification
A descriptive term for tenacity where a mineral breaks easily with a lack of flexibility or elasticity.
A group name for platy phyllosilicates of 2:1 layer and a layer charge of ~ -2.0 per formula unit. Rieder et al. (1998) defines the brittle micas as having greater than 50% of the interlayer cations as divalent. Brittle micas do not have swelling capacity. Common divalent cations in the interlayer include Ca and Ba. The subgroups of the brittle micas are based on dioctahedral or trioctahedral character, and species within the subgroups are based on chemical composition.
Cf., mica, true mica, interlayer-deficient mica, group names
An obsolete varietal term for clintonite.
An obsolete name for astrophyllite.
Brucite is a hydroxide mineral with the composition of Mg(OH)2. Also, brucite has been used as a group name for M2+(OH)2 where M = Fe, Mg, Mn, Ni. Brucite is comprised of a plane of Mg cations, with each Mg octahedrally coordinated by edge-sharing OH groups, thus forming an infinite two-dimensional sheet. Brucite primarily occurs as a contact metmorphic mineral in dolomites and Mg-rich limestones from the alteration of periclase, and in serpentinites and chlorite schists.
Inappropriate usage for trioctahedral sheet.
See trioctahedral sheet, interlayer material
Surface area determination by sorption analysis of non-polar gases, typically N2, on a solid, as calculated from the linear form of the BET equation (see Brunauer et al., 1938) for multi-layer gas adsorption on the surface of a sample of known weight. The technique requires removal of sorbed gases from the sample prior to BET analysis. Objections involving the use of BET analysis for clays containing H2O include 1) platy surfaces of the phyllosilicate particles protect underlying adjacent surfaces from gas adsorption, and 2) interlayer regions may become inaccessible to N2 owing to pretreatments that remove interlayer H2O, which collapses any swelling clays present, and thus results may be affected by preparation techniques. It is commonly considered to measure external surface area and, as such, should not be used for total specific surface area or as an indicator of the amount of chemically accessible internal surface area.