a) in mineralogy, a crystal shape that is an expression of the ordered pattern of the atomic structure. The crystal form is commonly a regular geometric shape.
b) in crystallography, a form consists of a group of symmetry-related crystal faces.
a) in mineralogy, a crystal shape that is an expression of the ordered pattern of the atomic structure. The crystal form is commonly a regular geometric shape.
b) in crystallography, a form consists of a group of symmetry-related crystal faces.
The number of gram formula weights (= molecular weights) of the solute in one liter of solution. Useful where experiments use measured volumes and where temperature effects are not being studied.
Cf., molarity, normality, molality, mole fraction
See tobermorite.
The Zn-rich, platy serpentine defined ideally as Zn3(Si,Al)2O5(OH)4. Cu, Al, and vacancies are known to substitute for Zn. Occurrences include Gleeson, Arizona, USA, and Laurion, Greece (both Cu-rich), Defiance, Belgium, and Tsumeb, Namibia.
An intermediate structure between chlorite and brittle micas (Peacor et al., 1988). The franklinfurnaceite structure is similar to chlorite-IIa-1 polytype with a trioctahedral 2:1 layer, but with a dioctahedral interlayer (thus, tri-dioctahedral). It differs from chlorite and is more mica-like because Ca cations occupy octahedral sites between the tetrahedral sheets and the dioctahedral interlayers. Franklinfurnaceite is ideally Ca2Fe3+Mn2+3Mn3+[Zn2Si2O10](OH)8 and occurs at Franklin, New Jersey, USA.
The Mn analogue of stilpnomelane.
See stilpnomelane
An obsolete term for muscovite.
A free-swell test is a process- or quality-control test to measure the compatibility of a clay with various solvents by placing a specified amount of clay in the fluid of interest, allowing it to remain undisturbed, and by determining the amount of swelling after a specified time. A graduated cylinder is often used to judge the amount of swelling after one or two hours, and 1 gram of clay is typically used, although each manufacturer/supplier follows their own protocols. The test is relative to a clay with no swelling behavior, as there are no standard-swelling behaviors. The test is especially useful to determine the optimum organoclay for paint or grease formulations.
A dehydration process where material is dried via sublimation of contained water. The material is frozen in a vessel, subjected to gas-pressure reduction often followed by slight heating, and dried by removal of sublimated water vapor. In clay mineralogy, samples of clay are dispersed in water as a suspension prior to freeze drying. The residual clay often shows the aggregate structure and fabric of the dispersed phase.
The characteristic of a solid material that allows its particle size to be easily reduced.