An obsolete varietal term for manganoan zincian chamosite.
See chlorite

An ammonia-dominated feldspar mineral, NH₄(Si₃Al)O₈.
Cf., alkali feldspar, feldspar, plagioclase feldspar

A poorly defined material, possibly biotite and vermiculite or interlayer-deficient biotite.

See astrophyllite group.

A measure of the resistance of a material to external stress, in units of pressure (usually gigapascals), by fitting the incremental change in potential energy with incremental change in volume (e.g., Birch-Murnaghan equation of state). The bulk modulus is measured by experiments or by simulations and best describes isotropic materials.
Cf., elastic constant.

A synthetic phase.
See birnessite

See plagioclase feldspar.