Mineralogy Database

Montmorillonite Mineral Data

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General Montmorillonite Information

Help on Chemical  Formula: Chemical Formula: (Na,Ca)0,3(Al,Mg)2Si4O10(OH)2•n(H2O)
Help on Composition: Composition: Molecular Weight = 549.07 gm
   Sodium     0.84 %  Na    1.13 % Na2O
   Calcium    0.73 %  Ca    1.02 % CaO
   Aluminum   9.83 %  Al   18.57 % Al2O3
   Silicon   20.46 %  Si   43.77 % SiO2
   Hydrogen   4.04 %  H    36.09 % H2O
   Oxygen    64.11 %  O
            ______        ______ 
            100.00 %      100.58 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Na0.2Ca0.1Al2Si4O10(OH)2(H2O)10
Help on IMA Status: IMA Status: Valid Species (Pre-IMA) 1847
Help on Locality: Locality: Veinne, Montmorillone, France. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named after the locality.
Help on Name Pronunciation: Name Pronunciation: Montmorillonite + Pronunciation Say MONTMORILLONITE
Help on Synonym: Synonym: Bentonite
 

Montmorillonite Image

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  Montmorillonite

Comments: Authigenic smectite (montmorillonite) overgrown on pore spaces and authigenicly-overgrown quartz grains in a sandstone. SEM image of a core sample.
Location: Unknown. Scale: Picture size 67 µ-m.
© OMNI Laboratories, Inc

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  Montmorillonite

Comments: Bright pink chalky massive montmorillonite.
Location: Tamminen Quarry, Greenwood, Oxford County, Maine, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Montmorillonite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.5782:1:1.1129
Help on Cell Dimensions: Cell Dimensions: a = 5.17, b = 8.94, c = 9.95, Z = 1; beta = 99.9° V = 453.04 Den(Calc)= 2.01
Help on Crystal System: Crystal System: Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/m
 

Physical Properties of Montmorillonite

Help on Cleavage: Cleavage: {001} Perfect
Help on Color: Color: White, Gray white, Yellow, Brownish yellow, Greenish yellow.
Help on Density: Density: 2 - 2.7, Average = 2.35
Help on Diaphaneity: Diaphaneity: Translucent to Opaque
Help on Fracture: Fracture: Earthy - Dull, clay-like fractures with no visible crystalline affinities, (e.g. howlite).
Help on Habit: Habit: Earthy - Dull, clay-like texture with no visible crystalline affinities, (e.g. howlite).
Help on Hardness: Hardness: 1.5-2 - Talc-Gypsum
Help on Luminescence: Luminescence: Non-fluorescent.
Help on Luster: Luster: Earthy (Dull)
Help on Streak: Streak: white
 

Optical Properties of Montmorillonite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.135 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.012 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2595,KPDmeas= 0.2219,KC= 0.2565
Ncalc = 1.51 - 1.69
Help on Optical Data: Optical Data: Biaxial (-), a=1.485-1.535, b=1.504-1.55, g=1.505-1.55, bire=0.0150-0.0200, 2V(Calc)=0-24, 2V(Meas)=5-30. Dispersion none.
Help on Pleochroism (x): Pleochroism (x): colorless.
Help on Pleochroism (y): Pleochroism (y): colorless.
Help on Pleochroism (z): Pleochroism (z): colorless.
 

Calculated Properties of Montmorillonite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.08 gm/cc
note: Specific Gravity of Montmorillonite =2.01 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0098785928
Boson Index = 0.9901214072
Help on Photoelectric: Photoelectric: PEMontmorillonite = 1.26 barns/electron
U=PEMontmorillonite x rElectron Density= 2.63 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Montmorillonite is Not Radioactive
 

Montmorillonite Classification

Help on  Dana Class: Dana Class: 71.03.01a.02 (71)Phyllosilicate Sheets of Six-Membered Rings
  (71.03)with 2:1 clays
  (71.03.01a)Smectite group (Dioctahedral Smectites)
 
71.03.01a.01 Beidellite Na0.5Al2(Si3.5Al0.5)O10(OH)2•n(H2O) C 2/m or ORTH 2/m
 
71.03.01a.02 Montmorillonite (Na,Ca)0,3(Al,Mg)2Si4O10(OH)2•n(H2O) C 2/m 2/m
 
71.03.01a.03 Nontronite Na0.3Fe2(Si,Al)4O10(OH)2•n(H2O) C 2/m 2/m
 
71.03.01a.04 Volkonskoite Ca0.3(Cr,Mg,Fe)2(Si,Al)4O10(OH)2•4(H2O) C 2/m 2/m
 
71.03.01a.05 Swinefordite (Li,Ca0.5,Na)0.72(Li,Al,Mg)2.66(Si,Al)4O10(OH,F)2•2(H2O) C 2/m (MON or ORTH) 2/m
Help on  Strunz Class: Strunz Class: 09.EC.40 09 - SILICATES (Germanates)
  09.E - Phyllosilicates
  09.EC -Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets
 
09.EC.40 Almbosite? Fe5Fe4V4Si3O27 Ortho ? Ortho
 
09.EC.40 Beidellite Na0.5Al2(Si3.5Al0.5)O10(OH)2•n(H2O) C 2/m or ORTH 2/m
 
09.EC.40 Kurumsakite (Zn,Ni,Cu)8Al8V2Si5O35•27(H2O)(?) Unk Ortho
 
09.EC.40 Montmorillonite (Na,Ca)0,3(Al,Mg)2Si4O10(OH)2•n(H2O) C 2/m 2/m
 
09.EC.40 Nontronite Na0.3Fe2(Si,Al)4O10(OH)2•n(H2O) C 2/m 2/m
 
09.EC.40 Volkonskoite Ca0.3(Cr,Mg,Fe)2(Si,Al)4O10(OH)2•4(H2O) C 2/m 2/m
 
09.EC.40 Yakhontovite (Ca,K)0.5(Cu,Fe,Mg)2Si4O10(OH)2•3(H2O) C 2/m 2/m
 

Other Montmorillonite Information

Help on References: References: NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)
Help on See Also: See Also: Links to other databases for Montmorillonite :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Amethyst Galleries' Mineral Gallery
5 - Athena
6 - EUROmin Project
7 - Ecole des Mines de Paris
8 - GeoScienceWorld
9 - Google Images
10 - Google Scholar
11 - Handbook of Mineralogy (MinSocAm)
12 - Handbook of Mineralogy (UofA)
13 - MinDAT
14 - Mineralienatlas (Deutsch)
15 - Online Mineral Museum
16 - QUT Mineral Atlas
17 - Ruff.Info
18 - Scandinavian mineral gallery

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Print or Cut-and-Paste your Montmorillonite Specimen Label here :

Montmorillonite

(Na,Ca)0,3(Al,Mg)2Si4O10(OH)2•n(H2O)
Dana No: 71.03.01a.02 Strunz No: 09.EC.40
Locality:

 

Notes:

 

 
   
 


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