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Montdorite Mineral Data

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General Montdorite Information

Help on Chemical  Formula: Chemical Formula: (K,Na)(Fe++,Mn++,Mg)2.5[Si4O10](F,OH)2
Help on Composition: Composition: Molecular Weight = 467.53 gm
   Potassium   6.27 %  K     7.56 % K2O
   Sodium      1.23 %  Na    1.66 % Na2O
   Magnesium   2.60 %  Mg    4.31 % MgO
   Manganese   9.40 %  Mn   12.14 % MnO
   Iron       14.33 %  Fe   18.44 % FeO
   Silicon    24.03 %  Si   51.41 % SiO2
   Hydrogen    0.11 %  H     0.96 % H2O
   Oxygen     35.93 %  O
   Fluorine    6.10 %  F     6.10 % F
                -   %   F    -2.57 % -O=F2    
             ______        ______ 
             100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: K0.75Na0.25Fe2+1.2Mn2+0.8Mg0.5Si4O10F1.5(OH)0.5
Help on Environment: Environment: Small grains in perialkaline rhyolite.
Help on IMA Status: IMA Status: Approved IMA 1979
Help on Locality: Locality: Mt. Dore stratovolcano, near La Bourboule, France. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for the locality.
Help on Name Pronunciation: Name Pronunciation: Montdorite + Pronunciation Say MONTDORITE
 

Montdorite Image

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  Montdorite

Comments: Pale green fine granular montdorite in iron-stained matrix.
Location: Charlunnes, Mont Dore, Puy-de-Dome, France. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Montdorite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.5771:1:1.1065
Help on Cell Dimensions: Cell Dimensions: a = 5.31, b = 9.2, c = 10.18, Z = 2; beta = 99.9° V = 489.91 Den(Calc)= 3.17
Help on Crystal System: Crystal System: Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/c
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.52(0.4), 3.41(0.4), 9.97(0.4),1.669(0.3), 2.17(0.3), 2.71(0.3), 3.14(0.3), 3.34(0.1),
 

Physical Properties of Montdorite

Help on Color: Color: Green, Brownish green.
Help on Diaphaneity: Diaphaneity: Translucent
Help on Habit: Habit: Microscopic Crystals - Crystals visible only with microscopes.
 

Optical Properties of Montdorite

Help on Gladstone-Dale: Gladstone-Dale: CI calc= 0.05 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1882,KC= 0.1982
Ncalc = 1.63
Help on Optical Data: Optical Data: Biaxial (-), a=1.58, b=1.605, g=1.605, bire=0.0250
 

Calculated Properties of Montdorite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=3.09 gm/cc
note: Specific Gravity of Montdorite =3.17 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PEMontdorite = 8.32 barns/electron
U=PEMontdorite x relectron= 25.76 barns/cc.
Help on Radioactivity: Radioactivity:

GRapi = 88.32 (Gamma Ray American Petroleum Institute Units)
Concentration of Montdorite per GRapi unit = 1.13 (%)

Estimated Radioactivity from Montdorite - barely detectable

 

Montdorite Classification

Help on  Dana Class: Dana Class: 71.02.02a.10 (71)Phyllosilicate Sheets of Six-Membered Rings
  (71.02)with 2:1 Layers
  (71.02.02a)Mica Group (Muscovite subgroup)
 
71.02.02a.01 Muscovite KAl2(Si3Al)O10(OH,F)2 C 2/m 2/m
 
71.02.02a.02 Paragonite NaAl2(Si3Al)O10(OH)2 C 2/c,Cc Mono
 
71.02.02a.03 Chernykhite (Ba,Na)V,Al)2(Si,Al)4O10(OH)2 C 2/c 2/m
 
71.02.02a.04 Roscoelite K(V,Al,Mg)2AlSi3O10(OH)2 C 2/m 2/m
 
71.02.02a.05 Glauconite (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2 C 2/m 2/m
 
71.02.02a.06 Celadonite K(Mg,Fe)(Fe,Al)[Si4O10](OH)2 C 2/m 2/m
 
71.02.02a.06b Ferroceladonite! K2FeFeSi8O20(OH)4 C 2/m 2/m
 
71.02.02a.06c Ferroaluminoceladonite! K2Fe2Al2Si8O20(OH)4 C 2/m 2/m
 
71.02.02a.06d Aluminoceladonite! KAl(Mg,Fe)[]Si4O10(OH)2 2/m
 
71.02.02a.06e Chromceladonite! KCrMg(Si4O10)(OH)2 C 2 2
 
71.02.02a.07 Tobelite (NH4,K)Al2(Si3Al)O10(OH)2 C 2/m 2/m
 
71.02.02a.08 Nanpingite Cs(Al,Mg,Fe,Li)2(Si3Al)O10(OH,F)2 C 2/c 2/m
 
71.02.02a.09 Boromuscovite KAl2(Si3B)O10(OH,F)2 C 2/m 2/m
 
71.02.02a.10 Montdorite (K,Na)(Fe,Mn,Mg)2.5[Si4O10](F,OH)2 C 2/c 2/m
 
71.02.02a.11 Chromphyllite! (K,Ba)(Cr,Al)2[AlSi3O10](OH,F)2 C 2c 2/m
 
71.02.02a.12 Shirokshinite! K(NaMg2)Si4O10F2 C 2/m 2/m
Help on  Strunz Class: Strunz Class: 09.EC.15 09 - SILICATES (Germanates)
  09.E - Phyllosilicates
  09.EC -Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets
 
09.EC.15 Boromuscovite KAl2(Si3B)O10(OH,F)2 C 2/m 2/m
 
09.EC.15 Celadonite K(Mg,Fe)(Fe,Al)[Si4O10](OH)2 C 2/m 2/m
 
09.EC.15 Chernykhite (Ba,Na)V,Al)2(Si,Al)4O10(OH)2 C 2/c 2/m
 
09.EC.15 Chromphyllite! (K,Ba)(Cr,Al)2[AlSi3O10](OH,F)2 C 2c 2/m
 
09.EC.15 Glauconite (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2 C 2/m 2/m
 
09.EC.15 Aluminoceladonite! KAl(Mg,Fe)[]Si4O10(OH)2 2/m
 
09.EC.15 Ferroaluminoceladonite! K2Fe2Al2Si8O20(OH)4 C 2/m 2/m
 
09.EC.15 Ferroceladonite! K2FeFeSi8O20(OH)4 C 2/m 2/m
 
09.EC.15 Montdorite (K,Na)(Fe,Mn,Mg)2.5[Si4O10](F,OH)2 C 2/c 2/m
 
09.EC.15 Nanpingite Cs(Al,Mg,Fe,Li)2(Si3Al)O10(OH,F)2 C 2/c 2/m
 
09.EC.15 Tobelite (NH4,K)Al2(Si3Al)O10(OH)2 C 2/m 2/m
 
09.EC.15 Roscoelite K(V,Al,Mg)2AlSi3O10(OH)2 C 2/m 2/m
 
09.EC.15 Muscovite KAl2(Si3Al)O10(OH,F)2 C 2/m 2/m
 
09.EC.15 Paragonite NaAl2(Si3Al)O10(OH)2 C 2/c,Cc Mono
 
09.EC.15 Tainiolite KLiMg2Si4O10F2 C 2/m 2/m
 
09.EC.15 Chromceladonite! KCrMg(Si4O10)(OH)2 C 2 2
 
09.EC.15 Ganterite! [Ba0.5(Na,K)0.5]Al2(Si2.5Al1.5O10)(OH)2 C 2/c 2/m
 

Other Montdorite Information

Help on References: References: NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)
Help on See Also: See Also: Links to other databases for Montdorite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info

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

Montdorite

(K,Na)(Fe++,Mn++,Mg)2.5[Si4O10](F,OH)2
Dana No: 71.02.02a.10 Strunz No: 09.EC.15
Locality:

 

Notes:

 

 
   
 


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