See zussmanite.

See hollandite.

A regular interstratification of trioctahedral chlorite-like layers with either trioctahedral smectite-like or trioctahedral vermiculite-like layers, the former being “low-charge corrensite” and the latter “high-charge corrensite”. The ratio of chlorite-like layers to smectite-like or vermiculite-like layers is 1:1 (Guggenheim et al., 2006). Corrensite occurrences are from low temperature environments, such as evaporites, saline deposits, sedimentary rocks, weathering zones, hydrothermal systems, burial diagenesis, low grade metamorphic regimes, and some contact metamorphic zones. Beaufort et al. (1997) discussed corrensite possibly as a regular mixed-layer structure involving a continuous series from smectite (or vermiculite) to chlorite or alternatively, as a single phase with a regular alteration of chlorite and smectite (or vermiculite) layers, with a stability field. If the latter, mixtures that deviate from 1:1 ratios of interstratified layers would require physical mixtures of appropriate layers of corrensite and chlorite.

An obsolete term for margarite.

An obsolete term for low-Si (and variable amounts of Fe₂O₃) chlorite.

The United States Federal Food, Drug, and Cosmetic Act (FD&C Act) of 13 March 2013 defines cosmetics by their intended use, as “articles intended to be rubbed, poured, sprinkled, or sprayed on, introduced into, or otherwise applied to the human body…for cleansing, beautifying, promoting attractiveness, or altering the appearance” [FD&C Act, sec. 201(i)]. The act specifically excludes soap as a cosmetic. Clays and clay minerals used in cosmetics include bentonite, illite, kaolin, iron oxides, etc., often characterized by color or locality, and each purported to function or behave differently.

An obsolete varietal term for paragonite.

For classical calculations or simulations of atomic structures, Coulomb interactions account for the attraction or repulsion between pairs of atoms in accord with the positive or negative charge on each atom. Coulomb’s Law is used to calculate the potential energy between each pair of atoms in the model system. For periodic systems, the long-range component of these interactions is often treated in reciprocal space by Ewald summation or a similar technique.
Syn., Coulombic interactions, electrostatic interactions;
Cf., Ewald sum, force field

An ion with a charge opposite in sign to the charge of the solid interface to which it is attracted.
Cf., co-ion

A chemical bond that involves sharing of one or more electrons, generally an electron pair. Covalent bonds require the appropriate geometric arrangement of coordinating atoms so that orbitals can overlap. Diamond, which involves carbon atoms, exhibits the ideal characteristics of covalent bonds. However, many elemental pairs involve covalent character and other bonding character (i.e., covalent plus ionic character as in the Si-O bond).