An indurated, fine-grained sedimentary rock composed of >66% clay-sized constituents with lamination (stratification of <10 mm thickness), after Potter et al. (2005). See clay, claystone, mud, mudrock, mudshale, mudstone, silt, siltstone.

A fine-grained sedimentary rock having >66% clay-size constituents and little or no sand, with stratification (i.e., bedding) of >10 mm thickness. Bedding within the claystone may be massive (after Potter et al., 2005).
See clay, clayshale, mud, mudrock, mudshale, mudstone, silt, siltstone.

The tendency of a crystal to break along certain (and generally smooth) planes of weakness. Planes of weakness in a crystal usually reflect either the presence of a plane of weaker or fewer bonds in a structure, and thus cleavage is a diagnostic property. These planes can be described as Miller indices, and are thus rational.
Cf., parting

An obsolete term for margarite.

a) Clinker, in materials science, is a sinter product of limestone and clay (or other secondary raw materials such as fly ash, sand, or slag) heated in kilns. Clinker is used as the primary component for Portland cement and is typically composed of calcium silicate (CS) phases such as “alite” (Ca₃SiO₅, “C₃S”), “belite” (Ca₂SiO₄, “C₂S”), or “celite” (Ca₃Al₂O₆, “C₃A”).

b) Clinker, in geological sciences, refers to a sedimentary bed that has undergone combustion, such as a coal bed that has undergone combustion and alteration by an igneous intrusion or by a coal-bed fire. Clinker may also refer to a pyroclastic or lava mass that resembles furnace slag.
Cf., calcium silicate phases; fly ash; slag, blast-furnace; kiln, rotary; Portland cement.

The trioctahedral Mg-rich member of the chlorite group.
See chlorite

A monoclinic (P2,sub>1/c) polymorph of enstatite. It is a product of fast cooled protoenstatite. Clinoenstatite occurs in Mg-rich basaltic rocks.

See zeolite.

A pyroxene subgroup of Ca-, Na-bearing pyroxenes with monoclinic (C2/c, P2₁/c) symmetry.
See pyroxene group for additional details.

See tobermorite.