C nonvitreous, porous, opaque ceramic whiteware made from milled clay, quartz,and feldspar, fired to between 950 – 1100°C. Water adsorption is variously defined as greater than 3% or greater than 5%. The material may be glazed to achieve water tightness. Earthenware is commonly used for flower pots, vases, or tile art.
Cf., ceramic, glaze, tile

Having a dull luster, similar to soil, usually involving an aggregate of fine-grained material.

A trioctahedral member of the true mica group. The ideal end-member formula is KMg₂Al(Al₂Si₂)O₁₀(OH)₂, although such a chemical composition has not been reported. The original eastonite occurrence from Easton, Pennsylvania, USA, was shown to be a mixture of phlogopite and lizardite-1T with some “antigorite-like offsets”. The eastonite composition is useful to describe solid solution series where there are Mg + Al substitutions.
Cf., presiwerkite, siderophyllite

An edge site is a binding site located on a non-basal (edge) surface of a clay mineral.
Cf., binding site

In classic soil mechanics, effective stress of a saturated clay body is the difference between the total stress and the pore water pressure. However, at the microscopic scale, effective stress must consider the actual stress involving forces transferred through particle contacts. In the stress range of interest to soil engineers, both water and soil particles are assumed incompressible, and hence the soil properties and mechanical behavior are controlled by forces involving inter-particle contacts only.

In geology, the weathering process where salt laden ground water is brought to the surface of a geologic material by evaporation, allowing the dissolved salts (e.g., halite, gypsum, calcite, natron) to crystallize forming a white/grey, often fluffy powder. Efflorescence is common in arid climates where rocks or soils of marine origin are exposed at or near the surface.

See ganophyllite.

See “deweylite”.

A 2:1 modulated phyllosilicate having an ideal chemical composition of KM₂₀Si₃₂O₇₆(OH)₁₇, where M = Fe²⁺, Mg, Mn²⁺. Analyses show that Ca and Na substitutes for K, Fe³⁺ substitutes for M, and Al substitutes for Si. Ekmanite has a highly disordered layer-stacking. The proposed model (Ferrow et al, 1999), based on TEM analysis, has strips of tetrahedra attached to the continuous octahedral sheet, with the strips along the a axis. The basic layer is 2:1 with inverted tetrahedra linking across the interlayer through apical oxygen atoms, with three of eight tetrahedra linking the 2:1 layers and inverted relative to adjacent octahedral sheets, similar to bannisterite. All tetrahedral rings are 6-fold, unlike bannisterite. Ekmanite is known from the magnetite ore body and skarns at Brunnsjögruvan, Sweden, in rocks metamorphosed to greenschist facies.

A descriptive term for tenacity where an applied force deforms a crystal, but the crystal resumes its original shape after the applied force is released.
Cf., flexible, brittle