The fabric of a soil or sediment ground mass where the fine material is described from the birefringence (“b-fabric”) based on the interference colors in thin section under crossed polarizers (after Bullock et al., 1985). Syn. clay birefringent fabric; see listing. Types of b-fabric relating to clay or other fine material include:

– cross striated b-fabric : Similar in description to reticulate striated b-fabric but with birefringent streaks showing non-perpendicular angular relationships in the ground mass.

– granostriated b-fabric : A b-fabric consisting of clay particles oriented parallel to skeletal grain surfaces.

– monostriated b-fabric : A fabric with birefringent streaks that are not associated with natural surfaces and occur isolated in the ground mass.

– mosaic-speckled b-fabric : A speckled b-fabric where a mosaic-like pattern occurs of coalescing birefringent regions or speckles.

– parallel striated b-fabric : A fabric with birefringent streaks that are not associated with natural surfaces and occur in parallel or sub- parallel sets in the ground mass.

– porostriated b-fabric : A striated b-fabric that consists of clay particles oriented parallel to the surface of pores.

– reticulate striated b-fabric : A ground mass with two sets of birefringent streaks intersecting at right angles. The streaks are not apparently associated with natural surfaces.

– speckled b-fabric : A ground mass (or pedoplasma or s-matrix) of predominantly clay where zones of birefringence show small (several microns), equidimensional, or slightly prolate regions or “speckles”.

– stipple-speckled b-fabric : A speckled b-fabric that consists of isolated regions or speckles.

– strial b-fabric : A ground mass composed mostly of clay characterized by preferred parallel birefringence orientation as an entity. This general orientation is commonly inherited from sedimentary processes and can occur in one or two preferred directions, “unistrial” and “bistrial”, respectively.

– striated b-fabric : A ground mass of predominantly clay with elongated birefringent zones or streaks showing nearly simultaneous extinction, commonly several hundred microns in size.

A poorly defined material, possibly muscovite and hematite.

See astrophyllite group.

The trioctahedral Zn-rich member of the chlorite group.
See Part 1. General terms: group names, chlorite

A member of the mica group characterized by octahedral vanadium and lithium and free from Al and OH, with a chemical composition of ideally KLi₂VSi₄O₁₂. Balestraite occurs in subgroup C2 symmetry because of octahedral ordering and as a 1M polytype. Balestraite occurs in Mn-rich beds within metacherts of an ophiolite sequence and was located between carbonate-rich and hematite bands at the Cerchiara mine, Eastern Liguria, Italy.

A fine-particle size, plastic, sedimentary kaolinitic clay layer with minor to abundant organic matter, important in the manufacture of ceramics. Typically found in association with lignite layers.
Cf., underclay, seat rock

The treatment of diseases, injuries, and other physical ailments by medicinal procedures in mineral springs, medical peloids or mud baths, inside the facilities of Health Resort Medicine Centers (Gutenbrunner et al., 2010). Balneotherapy is broadly interpreted to include hot or cold spring water baths, drinking of medical mineral waters rich in gases, salts, silica, sulfur, etc. Crenobalneotherapy is the term used in both France and southern Europe countries. Balnea is Latin for ‘hot baths’.

See picrolite.

A modulated, trioctahedral, mica-like layer silicate with cross-linked inverted tetrahedra with an idealized formula of Ca_0.5K_0.5M₁₀(Si_14.5Al_1.5)O₃₈(OH)₈ . nH₂O where M is medium-size divalent cations, such as Fe, Mn, Zn, Mg, and n = 2 – 6 (Heaney et al., 1992). The tetrahedral sheet consists of 5-, 6-, and 7-fold rings. Important localities for bannisterite include Franklin, New Jersey (USA), Broken Hill, Australia, and Nyberget, Sweden; localities with abundant Mn silicates.

See hydrotalcite group.