In soil science, permeability is a property of a soil or porous medium, which expresses the ease of a fluid flow (e.g., water, crude oil, gas, or air) through the medium, given in units of (length)2. In contrast, hydraulic conductivity refers specifically to water as the permeant.
Cf., hydraulic conductivity
See astrophyllite group.
An optical (transmitted visible light) microscope with polarizing filters or prisms along the optical path. The petrographic microscope is commonly used to examine thin sections and grain mounts.
See thin section, crossed Nichols, plane light.
The negative logarithmic (log10) measure of hydrogen ion (H+) activity which defines the acidity or alkalinity of a solution. In pure water, a value of 7 is neutral and represents an exact balance between the activities of hydrogen (H+) and hydroxide (OH–) ions. Values lower than 7 represent an increase in hydrogen ion activity and are acidic. Values higher than 7 represent a decrease in hydrogen ion activity and are alkaline.
The branch of knowledge concerned with medicinal drugs derived from natural products. This knowledge base includes the study of physical, chemical and biological properties of natural substances, for example, clays and clay minerals, used medicinally.
A part of a system with distinct chemical and physical properties that is mechanically separable from other parts of the system.
A graphical representation of the relationships involving possible phases that occur in a system, typically based on parameters such as temperature (T), pressure (P), composition (X), and typically at equilibrium conditions. However, other parameters may be used where convenient and non-equilibrium diagrams may be useful to show important phase relationships.
A series name to describe potassium-rich dioctahedral micas between or close to the muscovite-aluminoceladonite join and the muscovite-celadonite join (i.e., Al,Mg,Fe-containing).
A poorly defined material, possibly a decomposition product of biotite and vermiculite.
See zeolite.