The beginning of low-grade metamorphism. The epizone is defined by Kübler indices less than 0.25 in mudrock lithologies.
Cf., Kübler index

Symmetry equivalent points, which commonly refers to positions of symmetrically equivalent atoms in a crystal structure.

Clay particles are often size-separated using Stokes’ law, although Stokes’ law applies strictly to spherical particles only. Clay particles with platy shapes settle at slower rates than spheres of equal density in a fluid, however. If Stokes’ law is used in the size-separation analysis, it is appropriate to describe the platy clay particle as settling at velocity equal to that of a sphere of “equivalent” diameter (equivalent spherical diameter or esd or e.s.d.).
See Stokes’ Law

See zeolite.

Movement and removal of natural materials by the action of erosive agents, such as water, ice, and wind.
See weathering

An obsolete (light green) variety of parsettensite.

See equivalent spherical diameter; in statistics, this abbreviation is also used for estimated standard deviation.

A term broadly defined as a major element (e.g., H, O, C, N, Na, K, Ca, Mg, P, S, Cl) that plays physiologically important functions in human health. Essential elements can be derived through diet or through percutaneous migration from peloids.
See peloid
Cf., essential trace element;

A term for trace elements (e.g., Li, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, W, Mo, Si, Se, F, I, As, Br, Sn) required for human health and specific to the function of certain proteins and enzymes. An essential trace element may be derived through percutaneous migration or through diet.
Cf., trace element

See calcium silicate hydrate (CSH) in Part 1.