Mineralogy Database

Brammallite Mineral Data

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General Brammallite Information

Help on Chemical  Formula: Chemical Formula: (Na,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)]
Help on Composition: Composition: Molecular Weight = 391.86 gm
   Sodium      3.87 %  Na    5.22 % Na2O
   Magnesium   3.72 %  Mg    6.17 % MgO
   Aluminum   13.77 %  Al   26.02 % Al2O3
   Iron        1.43 %  Fe    1.83 % FeO
   Silicon    21.50 %  Si   46.00 % SiO2
   Hydrogen    1.28 %  H    11.47 % H2O
   Oxygen     54.43 %  O
             ______        ______ 
             100.00 %       96.71 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Na0.66(H3O)0.33AlMg0.6Fe2+0.1Si3AlO10(OH)2´┐Ż(H2O)
Help on Environment: Environment: Believed to be a degradation product of paragonite. Group name for Interlayer-deficient clays.
Help on IMA Status: IMA Status: Not Approved IMA 1998
Help on Locality: Locality: Landebie, Dyfed, Wales. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named in 1943 for Alfred Brammall (1879-?), British gologist and mineralogist.
Help on Name Pronunciation: Name Pronunciation: Brammallite + Pronunciation Say BRAMMALLITE
Help on Synonym: Synonym: Hydroparagonite
  Sodium hydromica
  Sodium illite

Brammallite Image

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Comments: Dark gray-brown fine grained massive brammallite.
Location: Near Ione, Amador County, California, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Brammallite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.5746:1:2.1616
Help on Cell Dimensions: Cell Dimensions: a = 5.12, b = 8.91, c = 19.26, Z = 4; beta = 95.83° V = 874.08 Den(Calc)= 2.98
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): 1.485(1), 9.77(1), 3.17(1),4.41(0.9), 2.54(0.9), 4.78(0.8), 2.11(0.6), 2.41(0.6),

Physical Properties of Brammallite

Help on Cleavage: Cleavage: {001} Perfect
Help on Color: Color: White.
Help on Density: Density: 2.83 - 2.88, Average = 2.85
Help on Diaphaneity: Diaphaneity: Translucent
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: 2.5-3 - Finger Nail-Calcite
Help on Luster: Luster: Earthy (Dull)
Help on Streak: Streak: white

Optical Properties of Brammallite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.065 (Fair) - where the CI = (1-KPDmeas/KC)
CI calc= 0.105 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1918,KPDmeas= 0.2002,KC= 0.2142
Ncalc = 1.61 - 1.64
Help on Optical Data: Optical Data: Biaxial (-), a=1.535-1.57, b=1.555-1.6, g=1.565-1.605, bire=0.0300-0.0350, 2V(Calc)=42-68, 2V(Meas)=5-25. 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 Brammallite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.87 gm/cc
note: Specific Gravity of Brammallite =2.86 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.01
Boson Index = 0.99
Help on Photoelectric: Photoelectric: PEBrammallite = 1.83 barns/electron
U=PEBrammallite x rElectron Density= 5.23 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Brammallite is Not Radioactive

Brammallite Classification

Help on  Dana Class: Dana Class: 71.02.02d.04 (71)Phyllosilicate Sheets of Six-Membered Rings
  (71.02)with 2:1 Layers
  (71.02.02d)Mica Group (Hydromica subgroup)
71.02.02d.01 Hydrobiotite [K(Mg,Fe)3(Al,Fe)Si3O10(OH,F)2]•[(Mg,Fe,Al)3(Si,Al)4O10(OH)2•4(H2O)] C 2/m 2/m
71.02.02d.02 Illite* (K,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)] C 2/m 2/m
71.02.02d.03 Vermiculite (Mg,Fe,Al)3(Al,Si)4O10(OH)2•4(H2O) C 2/m 2/m
71.02.02d.04 Brammallite* (Na,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)] C 2/c 2/m
Help on  Strunz Class: Strunz Class: 09.EC.25 09 - SILICATES (Germanates)
  09.E - Phyllosilicates
  09.EC -Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets
09.EC.25 Brammallite* (Na,H3O)(Al,Mg,Fe)2(Si,Al)4O10[(OH)2,(H2O)] C 2/c 2/m

Other Brammallite Information

Help on References: References: NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)
Help on See Also: See Also: Links to other databases for Brammallite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - GeoScienceWorld
5 - Google Images
6 - Google Scholar
7 - MinDAT
8 - Mineralienatlas (Deutsch)
9 - Online Mineral Museum
10 - QUT Mineral Atlas
11 - Ruff.Info

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Dana No: 71.02.02d.04 Strunz No: 09.EC.25





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