Mineralogy Database

Eggletonite Mineral Data

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General Eggletonite Information

Help on Chemical  Formula: Chemical Formula: Na2Mn8[Si11AlO29](OH)7•11(H2O)
Help on Composition: Composition: Molecular Weight = 1,602.61 gm
   Sodium      2.87 %  Na    3.87 % Na2O
   Manganese  27.42 %  Mn   35.41 % MnO
   Aluminum    1.68 %  Al    3.18 % Al2O3
   Silicon    19.28 %  Si   41.24 % SiO2
   Hydrogen    1.82 %  H    16.30 % H2O
   Oxygen     46.92 %  O
             ______        ______ 
             100.00 %      100.00 % = TOTAL OXIDE
Help on Empirical Formula: Empirical Formula: Na2Mn2+8Si11AlO29(OH)7•11(H2O)
Help on Environment: Environment: Miarolitic cavities in nepheline syenite. Probably isostructural with ganophyllite.
Help on IMA Status: IMA Status: Approved IMA 1984
Help on Locality: Locality: Big Rock Quarry, Little Rock, Pulaski County, Arkansas, USA. Link to MinDat.org Location Data.
Help on Name Origin: Name Origin: Named for R. A. Eggleton, Australian National University.
Help on Name Pronunciation: Name Pronunciation: Eggletonite + Pronunciation Say EGGLETONITE

Eggletonite Image

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Comments: Brown micro crystals of eggletonite in syenite.
Location: 3M Quarry, Little Rock, Pulaski County, Arkansas, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Eggletonite Crystallography

Help on Axial Ratios: Axial Ratios: a:b:c =0.4048:1:1.8221
Help on Cell Dimensions: Cell Dimensions: a = 5.554, b = 13.72, c = 25, Z = 2; beta = 93.95° V = 1,900.50 Den(Calc)= 2.80
Help on Crystal System: Crystal System: Monoclinic Space Group: Ia or I2/a
Help on X Ray Diffraction: X Ray Diffraction: By Intensity(I/Io): 2.694(1), 12(1), 2.598(0.55),

Physical Properties of Eggletonite

Help on Cleavage: Cleavage: {001} Perfect
Help on Color: Color: Golden brown.
Help on Density: Density: 2.76
Help on Fracture: Fracture: Brittle - Generally displayed by glasses and most non-metallic minerals.
Help on Habit: Habit: Acicular - Occurs as needle-like crystals.
Help on Habit: Habit: Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).
Help on Habit: Habit: Radial - Crystals radiate from a center without producing stellar forms (e.g. stibnite)
Help on Hardness: Hardness: 3-4 - Calcite-Fluorite
Help on Luster: Luster: Vitreous (Glassy)
Help on Streak: Streak: light brown

Optical Properties of Eggletonite

Help on Gladstone-Dale: Gladstone-Dale: CI meas= 0.045 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= 0.059 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2117,KPDmeas= 0.2147,KC= 0.2249
Ncalc = 1.62 - 1.63
Help on Optical Data: Optical Data: Biaxial (-), a=1.566, b=1.606, g=1.606, bire=0.0400, 2V(Calc)=0, 2V(Meas)=9.

Calculated Properties of Eggletonite

Help on Electron Density: Electron Density: Bulk Density (Electron Density)=2.73 gm/cc
note: Specific Gravity of Eggletonite =2.76 gm/cc.
Help on Fermion Index: Fermion Index: Fermion Index = 0.0092304868
Boson Index = 0.9907695132
Help on Photoelectric: Photoelectric: PEEggletonite = 7.73 barns/electron
U=PEEggletonite x rElectron Density= 21.13 barns/cc.
Help on Radioactivity: Radioactivity: GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Eggletonite is Not Radioactive

Eggletonite Classification

Help on  Dana Class: Dana Class: (74)Phyllosilicate Modulated Layers
  (74.01)with joined islands
  (74.01.02)Ganophyllite group Ganophyllite (K,Na)2(Mn,Al,Mg)8(Si,Al)12O29(OH)7•8-9(H2O) A2/a 2/m Eggletonite Na2Mn8[Si11AlO29](OH)7•11(H2O) Ia or I2/a Mono Tamaite! (Ca,K,Ba,Na)3-4Mn24(Si,Al)40(O,OH)112•21(H2O) P 21/a 2/m
Help on  Strunz Class: Strunz Class: 09.EG.30 09 - SILICATES (Germanates)
  09.E - Phyllosilicates
  09.EG -Double nets with 6-membered and larger rings
09.EG.30 Eggletonite Na2Mn8[Si11AlO29](OH)7•11(H2O) Ia or I2/a Mono
09.EG.30 Ganophyllite (K,Na)2(Mn,Al,Mg)8(Si,Al)12O29(OH)7•8-9(H2O) A2/a 2/m
09.EG.30 Tamaite! (Ca,K,Ba,Na)3-4Mn24(Si,Al)40(O,OH)112•21(H2O) P 21/a 2/m

Other Eggletonite Information

Help on References: References: NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)
Help on See Also: See Also: Links to other databases for Eggletonite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info

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Dana No: Strunz No: 09.EG.30





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