Eckermannite Mineral Data

General Eckermannite Information

Chemical Formula:

NaNa2(Mg4Al)Si8O22(OH)2

Composition:

Molecular Weight = 803.86 gm

Sodium 8.58 % Na 11.57 % Na₂O

Magnesium 12.09 % Mg 20.06 % MgO

Aluminum 3.36 % Al 6.34 % Al₂O₃

Silicon 27.95 % Si 59.80 % SiO₂

Hydrogen 0.25 % H 2.24 % H₂O

Oxygen 47.77 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Na₃Mg₄Al(Si₈O₂₂)(OH)₂

IMA Status:

Valid Species (Pre-IMA) 1942

Locality:

Link to MinDat.org Location Data.

Name Origin:

Named as per current IMA amphibole nomenclature (Burke and Leake 2004; Can. Mineral., 42, 1881-1883).

Name Pronunciation:

Eckermannite + Pronunciation

Eckermannite Image

Images:

Eckermannite

Comments: Dark blue-green prismatic crystalline eckermannite in matrix.
Location: Norra Karr, Granna, Jonkoping, Sweden. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Eckermannite Crystallography

Axial Ratios:

a:b:c =0.5456:1:0.2953

Cell Dimensions:

a = 9.762, b = 17.892, c = 5.284, Z = 2; beta = 103.2° V = 898.53 Den(Calc)= 2.97

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: C 2/m

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 3.1(1), 2.71(0.8), 3.4(0.7),

Crystal Structure:

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Raudsepp M , Turnock A C , Hawthorne F C , American Mineralogist , 72 (1987) p.959-964, Characterization of cation ordering in synthetic scandium-fluor-eckermannite,, indium-fluor-eckermannite, and scandium-fluor-nyboite by Rietveld structure, refinement, Sample: FScEC-A3

View Additional jPOWD Structure files for Eckermannite
[1]

Physical Properties of Eckermannite

Cleavage:

{110} Perfect

Color:

Blue green.

Density:

3 - 3.17, Average = 3.08

Diaphaneity:

Translucent

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Hardness:

5-6 - Between Apatite and Orthoclase

Luster:

Vitreous (Glassy)

Streak:

greenish white

Optical Properties of Eckermannite

Gladstone-Dale:

CI meas= 0.006 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.032 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2139,KPDmeas= 0.2059,KC= 0.2072
Ncalc = 1.62 - 1.66

Optical Data:

Biaxial (-), a=1.612-1.638, b=1.625-1.652, g=1.63-1.654, bire=0.0160-0.0180, 2V(Calc)=40-62, 2V(Meas)=80.

Calculated Properties of Eckermannite

Electron Density:

Bulk Density (Electron Density)=3.07 gm/cc
note: Specific Gravity of Eckermannite =3.09 gm/cc.

Fermion Index:

Fermion Index = 0.02
Boson Index = 0.98

Photoelectric:

PE_Eckermannite= 1.58 barns/electron
U=PE_Eckermannite x rElectron Density= 4.85 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Eckermannite is Not Radioactive

Eckermannite Classification

Dana Class:

66.01.03c.06 (66)Inosilicate Double-Width Unbranched Chains, W=2

(66.01)with P=2 amphibole configuration

(66.01.03c)Group 4, the sodic amphiboles

66.01.03c.01 Glaucophane []Na2(Mg3Al2)Si8O22(OH)2 C 2/m 2/m

66.01.03c.02 Ferroglaucophane []Na2(Fe3Al2)Si8O22(OH)2 C 2/m 2/m

66.01.03c.03 Crossite? Na2(Mg,Fe)3(Al,Fe)2Si8O22(OH)2 C 2/m 2/m

66.01.03c.04 Magnesioriebeckite []Na2[(Mg,Fe)3Fe2]Si8O22(OH)2 C 2/m 2/m

66.01.03c.05 Riebeckite []Na2(Fe3Fe2)Si8O22(OH)2 C 2/m 2/m

66.01.03c.06 Eckermannite NaNa2(Mg4Al)Si8O22(OH)2 C 2/m 2/m

66.01.03c.07 Ferro-eckermannite NaNa2(Fe4Al)Si8O22(OH)2 C 2/m 2/m

66.01.03c.08 Magnesio-arfvedsonite NaNa2(Mg4Fe)Si8O22(OH)2 C 2/m 2/m

66.01.03c.09 Arfvedsonite NaNa2(Fe4Fe)Si8O22(OH)2 C 2/m 2/m

66.01.03c.09a Fluoro-magnesio-arfvedsonite! NaNa2(Mg,Fe)4Fe[Si8O22](F,OH)2 C 2/m 2/m

66.01.03c.09b Potassicarfvedsonite! KNa2Fe4FeSi8O22(OH)2 C 2/m 2/m

66.01.03c.10 Kozulite NaNa2Mn4(Fe,Al)Si8O22(OH)2 C 2/m 2/m

66.01.03c.11 Nyboite NaNa2(Mg3Al2)Si7AlO22(OH)2 C 2/m 2/m

66.01.03c.11a Ferronyboite! NaNa2(Fe)3Al2(Si7Al)O22(OH)2 C 2/m 2/m

66.01.03c.11b Ferric-ferronyboite! NaNa2(Fe)3(Fe)2(Si7Al)O22(OH)2 C 2/m 2/m

66.01.03c.11c Fluoronyboite! NaNa2(Al2Mg3)(Si7Al)O22(F,OH)2 C 2/m 2/m

66.01.03c.12 Leakeite NaNa2(Mg2Fe2Li)Si8O22(OH)2 C 2/m 2/m

66.01.03c.12a Ferroleakeite! NaNa2(Fe)3(Fe)2Li(Si8O22)(OH)2 C 2/m 2/m

66.01.03c.12b Potassicleakeite! KNa2Mg2Fe2LiSi8O22(OH)2 C 2/m 2/m

66.01.03c.13 Kornite Na(CaNa)Fe4(Al,Fe)Si7AlO22(OH)2 C 2/m 2/m

66.01.03c.14 Ungarettiite NaNa2(Mn2Mn3)Si8O22O2 C 2/m 2/m

66.01.03c.15 Fluoro-ferroleakeite NaNa2(Fe2Fe2Li)Si8O22F2 C 2/m 2/m

66.01.03c.16 Obertiite! NaNa2(Mg3FeTi)Si8O22(O,F,OH)2 C 2/m 2/m

66.01.03c.17 Dellaventuraite! NaNa2(Mg2,Mn,Li,Ti)Si8O22O2 C 2/m 2/m

Strunz Class:

09.DE.25 09 - SILICATES (Germanates)

09.D - Inosilicates* Structural terminology according to Liebau (1985)

09.DE -Inosilicates with 2-periodic double chains, Si4O11; amphibole family

09.DE.25 Arfvedsonite NaNa2(Fe4Fe)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Ferroglaucophane []Na2(Fe3Al2)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Crossite? Na2(Mg,Fe)3(Al,Fe)2Si8O22(OH)2 C 2/m 2/m

09.DE.25 Eckermannite NaNa2(Mg4Al)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Glaucophane []Na2(Mg3Al2)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Fluoro-ferroleakeite NaNa2(Fe2Fe2Li)Si8O22F2 C 2/m 2/m

09.DE.25 Ferro-eckermannite NaNa2(Fe4Al)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Ferroleakeite! NaNa2(Fe)3(Fe)2Li(Si8O22)(OH)2 C 2/m 2/m

09.DE.25 Ferronyboite! NaNa2(Fe)3Al2(Si7Al)O22(OH)2 C 2/m 2/m

09.DE.25 Ferric-ferronyboite! NaNa2(Fe)3(Fe)2(Si7Al)O22(OH)2 C 2/m 2/m

09.DE.25 Obertiite! NaNa2(Mg3FeTi)Si8O22(O,F,OH)2 C 2/m 2/m

09.DE.25 Nyboite NaNa2(Mg3Al2)Si7AlO22(OH)2 C 2/m 2/m

09.DE.25 Magnesioriebeckite []Na2[(Mg,Fe)3Fe2]Si8O22(OH)2 C 2/m 2/m

09.DE.25 Kozulite NaNa2Mn4(Fe,Al)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Kornite Na(CaNa)Fe4(Al,Fe)Si7AlO22(OH)2 C 2/m 2/m

09.DE.25 Leakeite NaNa2(Mg2Fe2Li)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Magnesio-arfvedsonite NaNa2(Mg4Fe)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Ungarettiite NaNa2(Mn2Mn3)Si8O22O2 C 2/m 2/m

09.DE.25 Riebeckite []Na2(Fe3Fe2)Si8O22(OH)2 C 2/m 2/m

09.DE.25 Potassicleakeite! KNa2Mg2Fe2LiSi8O22(OH)2 C 2/m 2/m

09.DE.25 Fluoronyboite! NaNa2(Al2Mg3)(Si7Al)O22(F,OH)2 C 2/m 2/m

09.DE.25 Fluoro-magnesio-arfvedsonite! NaNa2(Mg,Fe)4Fe[Si8O22](F,OH)2 C 2/m 2/m

09.DE.25 Potassicarfvedsonite! KNa2Fe4FeSi8O22(OH)2 C 2/m 2/m

09.DE.25 Dellaventuraite! NaNa2(Mg2,Mn,Li,Ti)Si8O22O2 C 2/m 2/m

Other Eckermannite Information

References:

PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Eckermannite :
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
15 - WWW-MINCRYST

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

Eckermannite

NaNa2(Mg4Al)Si8O22(OH)2
Dana No: 66.01.03c.06 Strunz No: 09.DE.25
Locality:

Notes: