nontronite
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Nontronite is the iron(III) rich member of the smectite group of clay minerals. Nontronites typically have a chemical composition consisting of more than ~30% Fe2O3 and less than ~12% Al2O3 (ignited basis). Nontronite has very few economic deposits like montmorillonite. Like montmorillonite, nontronite can have variable amounts of adsorbed water associated with the interlayer surfaces and the exchangeable cations.
Key facts
- Mineral.name
- Nontronite
- Mineral.category
- Phyllosilicate minerals
- Mineral.group
- Smectite group
- Mineral.image
- Mineraly.sk - nontronit.jpg
- Mineral.imagesize
- 260px
- Mineral.caption
- Nontronite from Slovakia
- Mineral.formula
- (Ca0.5,Na)0.3FeIII2(Si,Al)4O10(OH)2·nH2O
- Mineral.IMAsymbol
- Non
- Mineral.strunz
- 9.EC.40
- Mineral.system
- Monoclinic
- Mineral.symmetry
- C2/m (no. 12)
- Mineral.color
- Yellow, olive-green, green, orange, brown
- Mineral.habit
- Earthy masses
- Mineral.cleavage
- Perfect basal
- Mineral.fracture
- Uneven
- Mineral.mohs
- 1.5 to 2
- Mineral.luster
- Earthy to dull
- Mineral.refractive
- nα = 1.530–1.580; nβ = 1.555–1.612; nγ = 1.560–1.615
via Wikipedia infobox
Wikidata facts
- Subclass of
- smectite mineral group
- Named after
- arrondissement of Nontron
- Image
- Mineraly.sk - nontronit.jpg
Show 7 more facts
- Nickel-Strunz 9th edition (updated 2009)
- 9.EC.40
- Commons category
- Nontronite
- Nickel-Strunz '10th ed', review of (9th ed/ 2009 update)
- 9.EC.40
- crystal system
- monoclinic crystal system
- IMA Mineral Symbol
- Non
- chemical formula
- Na₀.₃Fe₂((Si,Al)₄O₁₀)(OH)₂ * nH₂O
- Strunz 8th edition (series ID, updated)
- VIII/E.08a
via Wikidata · CC0
~3 min read
Encyclopedic overview
2 sectionsContents
- See also
- References
Nontronite is the iron(III) rich member of the smectite group of clay minerals. Nontronites typically have a chemical composition consisting of more than ~30% Fe2O3 and less than ~12% Al2O3 (ignited basis). Nontronite has very few economic deposits like montmorillonite. Like montmorillonite, nontronite can have variable amounts of adsorbed water associated with the interlayer surfaces and the exchangeable cations.
Ignoring the isomorphic substitution of Si by Al, with exchangeable cations compensating for the resulting negative electrical charges and their hydration water in the interlayers, the elemental composition of nontronite could be idealised as simply {{Chem2|Fe^{III}2Si4O10(OH)2}}.
Excerpted from Wikipedia’s “nontronite” article, available under the CC BY-SA 4.0 licence.