Grunerite Mineral Data

General Grunerite Information

Chemical Formula:

[ ]Fe++7Si8O22(OH)2

Composition:

Molecular Weight = 1,001.61 gm

Iron 39.03 % Fe 50.21 % FeO

Silicon 22.43 % Si 47.99 % SiO₂

Hydrogen 0.20 % H 1.80 % H₂O

Oxygen 38.34 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Fe²⁺₇(Si₈O₂₂)(OH)₂

IMA Status:

Valid Species (Pre-IMA) 1853

Locality:

Link to MinDat.org Location Data.

Name Origin:

Named for Louis Emmanuel Gruner (1809-1883), Swiss-French chemist who analyzed the mineral.

Name Pronunciation:

Grunerite + Pronunciation

Synonym:

Amosite

ICSD 24590

PDF 44-1401

Grunerite Image

Images:

Grunerite

Comments: Olive green fibrous crystal aggregates of grunerite in rock matrix.
Location: Michigamme, Iron County, Michigan, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Grunerite Crystallography

Axial Ratios:

a:b:c =0.5252:1:0.2925

Cell Dimensions:

a = 9.57, b = 18.22, c = 5.33, Z = 2; beta = 102.1° V = 908.72 Den(Calc)= 3.66

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): 8.33(1), 2.77(0.9), 3.07(0.8),

Crystal Structure:

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Finger L W , Mineralogical Society of America Special Paper , 2 (1969) p.95-100, The crystal structure and cation distribution of a grunerite, Locality: Wabush iron formation, Labrador, Canada

Physical Properties of Grunerite

Cleavage:

{110} Perfect, {???} Distinct

Color:

Ashen, Brown, Brownish green, Dark gray.

Density:

3.4 - 3.5, Average = 3.45

Diaphaneity:

Translucent to opaque

Fracture:

Sub Conchoidal - Fractures developed in brittle materials characterized by semi-curving surfaces.

Habit:

Columnar - Forms columns

Habit:

Fibrous - Crystals made up of fibers.

Habit:

Massive - Uniformly indistinguishable crystals forming large masses.

Hardness:

5-6 - Between Apatite and Orthoclase

Luminescence:

Non-fluorescent.

Luster:

Vitreous - Pearly

Streak:

colorless

Optical Properties of Grunerite

Gladstone-Dale:

CI meas= -0.004 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= 0.054 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1896,KPDmeas= 0.2011,KC= 0.2003
Ncalc = 1.68 - 1.73

Optical Data:

Biaxial (-), a=1.663-1.686, b=1.68-1.709, g=1.696-1.729, bire=0.0330-0.0430, 2V(Calc)=84-86, 2V(Meas)=90-70. Dispersion r > v.

Pleochroism (x):

colorless, colorless, or pale yellow.

Pleochroism (y):

colorless, pale yellow, or yellowish gray.

Pleochroism (z):

colorless, pale green, pale yellow, or pale greenish yellow.

Calculated Properties of Grunerite

Electron Density:

Bulk Density (Electron Density)=3.36 gm/cc
note: Specific Gravity of Grunerite =3.45 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Grunerite= 12.52 barns/electron
U=PE_Grunerite x rElectron Density= 42.08 barns/cc.

Radioactivity:

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

Grunerite Classification

Dana Class:

66.01.01.03 (66)Inosilicate Double-Width Unbranched Chains, W=2

(66.01)with P=2 amphibole configuration

(66.01.01)Group 1, the Mg-Fe-Mn-Li amphiboles (Monoclinic)

66.01.01.01 Magnesiocummingtonite (Mg,Fe)7Si8O22(OH)2 C 2/m 2/m

66.01.01.02 Cummingtonite []Mg7Si8O22(OH)2 C 2/m 2/m

66.01.01.03 Grunerite []Fe7Si8O22(OH)2 C 2/m 2/m

66.01.01.03b Permanganogrunerite! []Mn4(Fe)3(Si8O22)(OH)2 C 2/m 2/m

66.01.01.04 Manganocummingtonite Na(Na,Mn)2(Mg4,Fe)5Si8O22(OH)2 C 2/m 2/m

66.01.01.05 Manganogrunerite []Mn2Fe5Si8O22(OH) C 2/m 2/m

66.01.01.06 Magnesioclinoholmquistite? Li2(Mg,Fe)3Al2Si8O22(OH)2 C 2/m 2/m

66.01.01.07 Clinoholmquistite? [](Li2Mg3Al2)Si8O22(OH)2 C 2/m 2/m

66.01.01.08 Clinoferroholmquistite [](Li2Fe3Al2)Si8O22(OH)2 C 2/m 2/m

66.01.01.08a Ferri-clinoholmquistite! []Li2Mg3(Fe3)2(Si8O22)(OH)2 C 2/m 2/m

66.01.01.08b Ferri-clinoferroholmquistite! []Li2(Fe2Fe3)Si8O22(OH)2 C 2/m 2/m

66.01.01.09 Sodic-ferripedrizite! Na(LiNa)(Fe2Mg2Li)Si8O22(OH,F)2 C 2/m 2/m

66.01.01.09a Ferripedrizite! NaLi2(Fe2Mg2Li)Si8O22(OH)2 C 2/m 2/m

66.01.01.09b Sodic-ferri-ferropedrizite! NaLi2(Fe2Fe3)Si8O22(OH)2 C 2/m 2/m

66.01.01.09c Fluoro-sodic-pedrizite! NaLi2(Mg2Al2Li)S5Si8O22F2 C 2/m 2/m

Strunz Class:

09.DE.05 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.05 Ferro-anthophyllite []Fe7Si8O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Anthophyllite []Mg7Si8O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Ferrogedrite []Fe5Al2Si6Al2O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Gedrite []Mg5Al2Si6Al2O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Ferroholmquistite [](Li2Fe3Al2)Si8O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Holmquistite [](Li2Mg3Al2)Si8O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Cummingtonite []Mg7Si8O22(OH)2 C 2/m 2/m

09.DE.05 Clinoferroholmquistite [](Li2Fe3Al2)Si8O22(OH)2 C 2/m 2/m

09.DE.05 Grunerite []Fe7Si8O22(OH)2 C 2/m 2/m

09.DE.05 Magnesiocummingtonite (Mg,Fe)7Si8O22(OH)2 C 2/m 2/m

09.DE.05 Manganogrunerite []Mn2Fe5Si8O22(OH) C 2/m 2/m

09.DE.05 Magnesioanthophyllite? (Mg,Fe)7Si8O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Protomangano-ferro-anthophyllite! (Mn,Fe)2(Fe,Mg)5(Si4O11)2(OH)2 Pnmn 2/m 2/m 2/m

09.DE.05 Sodicgedrite NaMg6AlSi6Al2O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Sodic-ferro-anthophyllite! NaFe7Si8O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Sodic-ferrogedrite! NaFe6AlSi6Al2O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Sodicanthophyllite NaMg7Si8O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Permanganogrunerite! []Mn4(Fe)3(Si8O22)(OH)2 C 2/m 2/m

09.DE.05 Protoferro-anthophyllite! (Fe,Mn)2(Fe,Mg)5(Si4O11)2(OH)2 Pnmn 2/m 2/m 2/m

09.DE.05 Fluoro-sodic-pedrizite! NaLi2(Mg2Al2Li)S5Si8O22F2 C 2/m 2/m

09.DE.05 Sodic-ferri-ferropedrizite! NaLi2(Fe2Fe3)Si8O22(OH)2 C 2/m 2/m

09.DE.05 Manganocummingtonite Na(Na,Mn)2(Mg4,Fe)5Si8O22(OH)2 C 2/m 2/m

09.DE.05 Protoanthophyllite! (Mg,Fe)7Si8O22(OH)2 Pnmn 2/m 2/m 2/m

09.DE.05 Ferri-clinoferroholmquistite! []Li2(Fe2Fe3)Si8O22(OH)2 C 2/m 2/m

09.DE.05 Sodic-ferripedrizite! Na(LiNa)(Fe2Mg2Li)Si8O22(OH,F)2 C 2/m 2/m

09.DE.05 Ferripedrizite! NaLi2(Fe2Mg2Li)Si8O22(OH)2 C 2/m 2/m

Other Grunerite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Heinrich65)

See Also:

Links to other databases for Grunerite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - CalTech Mineral Spectroscopy
4 - EUROmin Project
5 - Ecole des Mines de Paris
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - HyperPhysics
12 - MinDAT
13 - Mineralienatlas (Deutsch)
14 - Online Mineral Museum
15 - QUT Mineral Atlas
16 - Ruff.Info
17 - WWW-MINCRYST

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

Grunerite

[ ]Fe++7Si8O22(OH)2
Dana No: 66.01.01.03 Strunz No: 09.DE.05
Locality:

Notes: