Chamosite Mineral Data

General Chamosite Information

Chemical Formula:

(Fe++,Mg,Fe+++)5Al(Si3Al)O10(OH,O)8

Composition:

Molecular Weight = 664.18 gm

Magnesium 5.49 % Mg 9.10 % MgO

Aluminum 8.12 % Al 15.35 % Al₂O₃

Iron 29.43 % Fe 32.45 % FeO / 6.01 % Fe₂O₃

Silicon 12.69 % Si 27.14 % SiO₂

Hydrogen 0.91 % H 8.14 % H₂O

Oxygen 43.36 % O

______ ______

100.00 % 98.19 % = TOTAL OXIDE

Empirical Formula:

Fe²⁺₃Mg_1.5AlFe³⁺_0.5Si₃AlO₁₂(OH)₆

Environment:

Metamorphosed iron deposits.

IMA Status:

Valid Species (Pre-IMA) 1820

Locality:

Chamoson, Rhone Valley, Switzerland. Link to MinDat.org Location Data.

Name Origin:

Named after its locality.

Synonym:

Brunsvigite

Daphnite

Delessite

Thuringite (Fe)

Chamosite Image

Images:

Chamosite

Comments: Dark green sectile massive chamosite.
Location: Jalgaon, Maharashtra, India. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Chamosite Crystallography

Axial Ratios:

a:b:c =0.5773:1:1.5282

Cell Dimensions:

a = 5.373, b = 9.306, c = 14.222, Z = 2; beta = 97.88° V = 704.40 Den(Calc)= 3.13

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): 3.52(1), 7.05(1), 2.52(0.9),

Crystal Structure:

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Walker J R , Bish D L , Clays and Clay Minerals , 40 (1992) p.319-322, Application of Rietveld refinement techniques to a disordered IIb Mg-chamosite, Locality: Lebanon, New Hampshire, USA

Physical Properties of Chamosite

Cleavage:

{001} Good

Color:

Gray, Greenish gray, Brown, Blackish green.

Density:

3 - 3.4, Average = 3.2

Diaphaneity:

Translucent to subtranslucent

Fracture:

Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Habit:

Oolitic - < 3mm rounded spherical grains.

Hardness:

3 - Calcite

Luster:

Vitreous - Dull

Streak:

grayish green

Optical Properties of Chamosite

Gladstone-Dale:

CI meas= 0.09 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.07 (Fair) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1991,KPDmeas= 0.1948,KC= 0.214
Ncalc = 1.64 - 1.73

Optical Data:

Biaxial (-), a=1.6, b=1.6, g=1.67, bire=0.0700, 2V(Calc)=0, 2V(Meas)=0-15.

Calculated Properties of Chamosite

Electron Density:

Bulk Density (Electron Density)=3.08 gm/cc
note: Specific Gravity of Chamosite =3.13 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Chamosite= 9.57 barns/electron
U=PE_Chamosite x rElectron Density= 29.50 barns/cc.

Radioactivity:

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

Chamosite Classification

Dana Class:

71.04.01.07 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.04)interlayered 1:1, 2:1, and octahedra

(71.04.01)Chlorite group (Tri-Dioctahedral)

71.04.01.01 Donbassite Al2[Al2.33][Si3AlO10](OH)8 C 2/m 2/m

71.04.01.02 Cookeite LiAl4(Si3Al)O10(OH)8 P 2₁/a 2/m

71.04.01.03 Sudoite Mg2(Al,Fe)3Si3AlO10(OH)8 C 2/m 2/m

71.04.01.04 Clinochlore (Mg,Fe)5Al(Si3Al)O10(OH)8 C 2/m 2/m

71.04.01.05 Nimite (Ni,Mg,Fe)5Al(Si3Al)O10(OH)8 C 2/m 2/m

71.04.01.06 Baileychlore (Zn,Al,[])3[Fe2Al][Si3AlO10](OH)8 C1,C1 Tri

71.04.01.07 Chamosite (Fe,Mg,Fe)5Al(Si3Al)O10(OH,O)8 C 2/m 2/m

71.04.01.08 Pennantite Mn5Al(Si3Al)O10(OH)8 C 2/m 2/m

71.04.01.09 Orthochamosite! (Fe,Mg,Fe)5Al(Si3Al)O10(OH,O)8 C3m-pseudoHEX Ortho

71.04.01.10 Borocookeite! Li(13x)Al(4-x)(BSi3)O10(OH,F)8[x=0-0.33] pseudo C 2/m 2/m

Strunz Class:

09.EC.55 09 - SILICATES (Germanates)

09.E - Phyllosilicates

09.EC -Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets

09.EC.55 Donbassite Al2[Al2.33][Si3AlO10](OH)8 C 2/m 2/m

09.EC.55 Baileychlore (Zn,Al,[])3[Fe2Al][Si3AlO10](OH)8 C1,C1 Tri

09.EC.55 Clinochlore (Mg,Fe)5Al(Si3Al)O10(OH)8 C 2/m 2/m

09.EC.55 Cookeite LiAl4(Si3Al)O10(OH)8 P 2₁/a 2/m

09.EC.55 Chamosite (Fe,Mg,Fe)5Al(Si3Al)O10(OH,O)8 C 2/m 2/m

09.EC.55 Franklinfurnaceite Ca2(Fe,Al)MnMn3Zn2Si2O10(OH)8 C 2 2

09.EC.55 Nimite (Ni,Mg,Fe)5Al(Si3Al)O10(OH)8 C 2/m 2/m

09.EC.55 Gonyerite Mn3[Mn3Fe][(Si,Fe)4O10](OH,O)8 pseudo-HEX Ortho

09.EC.55 Odinite (Fe,Mg,Al,Fe,Ti,Mn)2.5(Si,Al)2O5(OH)4 Cm m

09.EC.55 Orthochamosite (Fe,Mg,Fe)5Al(Si3Al)O10(OH,O)8 C3m-pseudoHEX Ortho

09.EC.55 Pennantite Mn5Al(Si3Al)O10(OH)8 C 2/m 2/m

09.EC.55 Sudoite Mg2(Al,Fe)3Si3AlO10(OH)8 C 2/m 2/m

09.EC.55 Glagolevite! NaMg6[Si3AlO10](OH,O)8•H2O C1 1

09.EC.55 Borocookeite! Li(13x)Al(4-x)(BSi3)O10(OH,F)8[x=0-0.33] pseudo C 2/m 2/m

Other Chamosite Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Chamosite :
1 - Alkali-Nuts(English)
2 - Alkali-Nuts(Francais)
3 - Am. Min. Crystal Structure Database
4 - Athena
5 - EUROmin Project
6 - Ecole des Mines de Paris
7 - Franklin Minerals(Dunn)
8 - GeoScienceWorld
9 - Google Images
10 - Google Scholar
11 - Handbook of Mineralogy (MinSocAm)
12 - Handbook of Mineralogy (UofA)
13 - MinDAT
14 - Mineral and Gemstone Kingdom
15 - Mineralienatlas (Deutsch)
16 - Online Mineral Museum
17 - QUT Mineral Atlas
18 - Ruff.Info

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

Chamosite

(Fe++,Mg,Fe+++)5Al(Si3Al)O10(OH,O)8
Dana No: 71.04.01.07 Strunz No: 09.EC.55
Locality:

Notes: