The process of changing a solid, often crystalline material, into an amorphous glass-like material by heating the solid to its melting point followed by sufficiently rapid cooling and solidification so that short-distance atomic ordering resulting in recrystalization does not occur. As vitrification proceeds, the porosity decreases. Devitrification is the reverse process.

The ratio of the empty space (void volume) of a soil or geomaterial to the volume of its solid particles.
Cf., porosity

A poorly defined material, possibly a weathering product of biotite or interlayer-deficient biotite.

See volkonskoite.

A dioctahedral member of the smectite group with the dominant octahedral cation of Cr. The layer charge may originate by either tetrahedral or octahedral substitutions.
Syn., volkhonskoite

An obsolete varietal term for zinnwaldite, lithian annite, lithian siderophyllite (‘Raven mica’ or ‘crow mica’ in Russian).

A discredited term for oriented intergrowths of hausmannite + jacobsite.