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LITHOEN

Mineral

Montmorillonite

A swelling clay of the smectite family, whose interlayer sites take up water and exchangeable cations.

Classification

formula
(Na,Ca)0.3(Al,Mg)2Si4O10(OH)2·nH2O
ima status
grandfathered
crystal system
monoclinic

How this record is known

1
Settled consensus
Cited as the accepted position of the discipline.

1 of 1 claims on this page cite at least one registered source. Counts describe how each statement is known, not how likely it is to be true.

What Lithoen records

Each claim states how it is known and cites its evidence.

Established(Na,Ca)0.3(Al,Mg)2Si4O10(OH)2·nH2O

Montmorillonite is an accepted mineral species in the IMA List of Minerals, with the CNMNC-approved formula (Na,Ca)0.3(Al,Mg)2Si4O10(OH)2·nH2O and IMA status “grandfathered”.

  • definition basis: IMA List of Minerals, September 2026 update, which is the authority on mineral species status.
  • precision note: An approved formula is an idealised composition; natural crystals of most species depart from it through substitution.

Evidence support: Supported by the cited evidence one source

Evidence: Commission on New Minerals, Nomenclature and Classification, International Mineralogical Association 2026 Primary authority

In the knowledge graph

Record last updated 2026-09-06. Corrections follow the published corrections policy; superseded claims are retained, never silently edited.