A temperature scale where the freezing point of pure water at one standard atmosphere is set to 32^o and the boiling point is set to 212^o.
Cf., Celsius, Kelvin

Loss of cohesiveness.

To determine how an applied stress can cause failure of a material, such as a soil mass, a failure envelope is drawn by determining a line of best fit tangent for several Mohr circles at failure. Thus, the failure envelope is the locus of all shear and normal stress points at failure for a given material. Soil strength depends upon the effective stress, and the size of the stress circles at failure varies with the stress level. By varying the stress level (e.g., the minor principle stress), the failure stress circle changes location and size, and the line that envelopes all these failure stress circles is the failure envelope. Usually it can be defined base on either effective stress or total stress, and hence it can be an effective stress envelope or a total stress envelope. The most widely used linear (Mohr-Coulomb) failure envelope is defined as tau = c + sigma[tan (phi)], where phi is the friction angle or the slope of the failure envelope, and c is the cohesion (soil strength) or the intercept of the failure envelope at the vertical axis (or the shear stress axis).
Syn., Mohr failure envelope
See also Mohr’s circle

A member of the palygorskite-sepiolite group with a composition of approximately (Ni_8-y-zR³⁺_y□z)(Si_12-xR³⁺_x)O₃₀(OH)₄(OH₂)₄.R²⁺_(x-y+2z)2(H₂O)₈, where R is a cation, □ are vacancies, and x, y, and z are compositional parameters.
See palygorskite-sepiolite group

The magnitude of electric charge per mole of electrons; has the value of F = 96,485 coulombs/mole.

A poorly defined material, probably a mixture of kaolin and nontronite.

A qualitative industrial term used to distinguish clays possessing high plasticity (i.e., “fat”) or only slight plasticity (i.e., “lean”). The term originates from a soil classification system (Unified Soil Classification System used in both engineering and geology).

An invalid name for a hypothetical end member.

See reyerite group.

See groutite.