Title
montmorillonite
Composition
(Na,Ca)0.3(Al,Mg)2Si4O10(OH)2·nH2O
Crystal System
Monoclinic
Status at Tsumeb
Believed valid
Abundance
Somewhat rare
Distribution
Country rocks (feldspathic sandstone).
Paragenesis
Rock-forming (detrital (?), diagenetic (?) ); supergene.
Type Locality
No
Entry Type
Species TSNB248
General Notes
Montmorillonite is an inconspicuous and somewhat rare component of the feldspathic sandstone, derived from the Tschudi Formation (Lombaard et al. 1986). Keller (1984) notes that montmorillonite (also kaolinite and phlogopite) occur very rarely as secondary minerals in the supergene environment.
Associated Minerals
albite; almandine; anorthite; biotite series; calcite; clinochlore; epidote; fluorapatite; graphite; ilmenite; magnetite; microcline; muscovite; orthoclase; quartz; rutile; titanite; tourmaline supergroup; zircon
