A dioctahedral member of the true mica group. The end-member formula is KAl₂□BSi₃O₁₀(OH)₂, where □ = vacancy. Boromuscovite occurs as 2M₁ and 1M polytypes and has been found in pegmatites at the Řečice pegmatite dikes, Czech Republic, where it occurs asfine-grained masses, and Little Three Mine pegmatite dike, San Diego County, California, USA, where it occurs as coatings from late-stage hydrothermal fluids.
Cf., borocookeite, manandonite, muscovite

The fused, amorphous, siliceous residue from burning coal in industrial burners. Crushed and sized bottom ash is used as an aggregate substitute in concrete and as a non-crystalline substitute for quartz sand in sand blasting.
Cf., fly ash

A transparent, yellow green variety of massive serpentine (antigorite?), used as an alternative for jade. Bowenite is not a mineral name and should not be used in the scientific literature.
Syn. tangiwaite or tangawaite (from New Zealand)

An obsolete term for bityite.

An obsolete term for a saponite-rich material from near Bowling, Dumbarton, Scotland.

Bragg’s law describes the condition for an X-ray reflection (i.e., constructive interference) for crystalline materials and is given as n λ = 2 d sinθ, where n is the path difference between reflecting planes, which must be an integer for constructive interference, λ is the wavelength, d is the interplanar spacing, and θ is the glancing angle of incidence (reflection angle). In an X-ray diffraction experiment, the λ is known and is dependent on the X-ray source in use,θ is the measured quantity, and d is the parameter that is characteristic of the material under study. Thus, both n and d are unknowns. In practice, the order of the reflection n is fixed for the value of d for a specific plane hkl (and thus is included in the value) and, the use of d_hkl symbolizes this inter-relationship. Thus, the modified version of the Bragg equation is used in practice, which is given as: λ = 2 d_hkl sinθ.

An aluminum-rich dioctahedral mica that shows interlayer deficiency and limited substitutions of Al in the tetrahedral sites. It is a series name (Rieder et al., 1998) with a generalized composition of Na_0.65Al₂□Al_0.65Si_3.35O₁₀(OH)₂. Series names designate that additional research may be warranted.

An obsolete varietal term for clintonite.

One of 14 different types of space lattices (three dimensional arrays). The Bravais lattices are characterized by identipoints showing translational periodicity, and this periodicity can be used to define a (unit) cell. There are five basic lattice types [P, A (or B or C), F, I, and R]. When distributed over the crystal systems, the five basic types produce 14 space lattices.
Cf., identipoint, lattice, array

A poorly defined material, possibly illite and montmorillonite.