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Cordierite

Formula:
(Mg,Fe)
 
2
Al
 
4
Si
 
5
O
 
18
System:OrthorhombicColour:Grey, blue, blue-violet, ...
Lustre:VitreousHardness:7 - 7½
Name:After Pierre Louis A. Cordier (1777-1861), French mining engineer and geologist, who first studied this species.
Dimorph of:Indialite


The Mg analogue of Sekaninaite. Cordierite-Sekaninaite Series.

Classification of Cordierite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:8/E.12-40
Nickel-Strunz 10th (pending) edition ID:9.CJ.10

9 : SILICATES (Germanates)
C : Cyclosilicates
J : [Si6O18]12- 6-membered single rings (sechser-Einfachringe), without insular complex anions
Dana 8th edition ID:61.2.1.1

61 : CYCLOSILICATES Six-Membered Rings
2 : Six-Membered Rings with Al substituted rings
Hey's CIM Ref.:16.19.2

16 : Silicates Containing Aluminum and other Metals
19 : Aluminosilicates of Fe and Mg
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Type Occurrence of Cordierite

Type Locality:Großer Arber Mt., Bayerisch Eisenstein, Zwiesel, Bavarian Forest, Lower Bavaria, Bavaria, Germany
Year of Discovery:1813

Occurrences of Cordierite

Geological Setting:Thermally metamorphosed argillaceous sedimentary rocks; high-grade regionally metamorphosed schists, gneisses and granulites; also in mafic igneous rocks and granites.

Physical Properties of Cordierite

Lustre:Vitreous
Diaphaneity (Transparency):Transparent, Translucent
Colour:Grey, blue, blue-violet, greenish, yellowish brown; colourless to very light blue in transmitted light.
Hardness (Mohs):7 - 7½
Tenacity:Brittle
Cleavage:Imperfect/Fair
On {100}, fair; On {001} and {010}, poor.
Fracture:Sub-Conchoidal
Density (measured):2.6 - 2.66 g/cm3
Density (calculated):2.505 g/cm3

Crystallography of Cordierite

Crystal System:Orthorhombic
Class (H-M):mmm (2/m 2/m 2/m) - Dipyramidal
Space Group:Cccm (C2/c 2/c 2/m)
Cell Parameters:a = 9.73Å, b = 17.08Å, c = 9.34Å
Ratio:a:b:c = 0.57 : 1 : 0.547
Unit Cell Volume:V 1,552.20 ų (Calculated from Unit Cell)
Morphology:Crystals short prismatic, striated parallel to [001]. Commonly granular to compact, massive.
Twinning:Common on {110} and {130}, simple, lamellar, and cyclical.
Crystal Atlas:
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Cordierite no.7 - Goldschmidt (1913-1926)
Cordierite no.30 - Goldschmidt (1913-1926)

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Structure
  Reference
Gibbs G V (1966) The polymorphism of cordierite I: The crystal structure of low cordierite. American Mineralogist 51:1068-1087.

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More Crystal Structures
Click here to view more crystal structures at the American Mineralogist Crystal Structure Database
X-Ray Powder Diffraction:
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Radiation - Copper Kα
Data Set:
Horizontal Axis: ° to ° Vertical Axis: % Source Data: Filtered Data: Peaks:
Data courtesy of RRUFF project at University of Arizona, used with permission.

Optical Data of Cordierite

Type:Biaxial (-)
RI values: nα = 1.527 - 1.560 nβ = 1.532 - 1.574 nγ = 1.538 - 1.578
2V:Measured: 75° to 89°, Calculated: 54° to 86°
Maximum Birefringence:δ = 0.011 - 0.018

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Low
Dispersion:r < v, weak to marked
Pleochroism:Strong
Comments:X = c = Pale yellow, green
Y = a = Violet, blue-violet
Z = b = Light blue

Chemical Properties of Cordierite

Formula:
(Mg,Fe)
 
2
Al
 
4
Si
 
5
O
 
18
Essential elements:Al, Mg, O, Si
All elements listed in formula:Al, Fe, Mg, O, Si
Common Impurities:Mn,Fe,Ti,Ca,Na,K

Relationship of Cordierite to other Species

Series:Forms a series with Sekaninaite (see here)
Common Associates:
SpinelSillimaniteMuscoviteK FeldsparGarnet Group
CorundumBiotiteAndalusite
Related Minerals - Nickel-Strunz Grouping):
9.CJ.05Bazzite
Be
 
3
Sc
 
2
Si
 
6
O
 
18
9.CJ.05Beryl
Be
 
3
Al
 
2
Si
 
6
O
 
18
9.CJ.05Indialite
Mg
 
2
Al
 
4
Si
 
5
O
 
18
9.CJ.05Stoppaniite
(Fe,Al,Mg)
 
4
(Na,[ ])
 
2
[Be
 
6
Si
 
12
O
 
36
]·2(H2O)
9.CJ.05Pezzottaite
Cs(Be
 
2
Li)Al
 
2
Si
 
6
O
 
18
9.CJ.10Sekaninaite
(Fe,Mg)
 
2
Al
 
4
Si
 
5
O
 
18
9.CJ.15Combeite
Na
 
2
Ca
 
2
Si
 
3
O
 
9
9.CJ.15Kazakovite
Na
 
6
Ti[Si
 
6
O
 
16
(OH)
 
2
]
9.CJ.15Lovozerite
(Na,Ca)
 
3
(Zr,Ti)[Si
 
6
(O,OH)
 
18
]
9.CJ.15Tisinalite
Na
 
3
H
 
3
(Mn,Ca,Fe)TiSi
 
6
(O,OH)
 
18
·2H
 
2
O
9.CJ.15Zirsinalite
Na
 
6
(Ca,Mn
2+
 
,Fe
2+
 
)Zr[Si
 
6
O
 
18
]
9.CJ.15Litvinskite
Na
 
2
([],Na,Mn)ZrSi
 
6
O
 
12
(OH,O)
 
6
9.CJ.15Kapustinite
Na
 
5
(Na,Mn
2+
 
)
 
<1
Zr[Si
 
6
O
 
16
(OH)
 
2
]
9.CJ.20Imandrite
Na
 
12
Ca
 
3
Fe
3+
2
[Si
 
6
O
 
18
]
 
2
9.CJ.20Koashvite
Na
 
6
(Ca,Mn)(Ti,Fe)Si
 
6
O
 
18
·H
 
2
O
9.CJ.25Baratovite
KCa
 
7
(Ti,Zr)
 
2
Li
 
3
Si
 
12
O
 
36
F
 
2
9.CJ.25Katayamalite
KCa
 
7
Ti
 
2
Li
 
3
Si
 
12
O
 
36
(OH)
 
2
9.CJ.30Dioptase
CuSiO
 
2
(OH)
 
2
9.CJ.35Kostylevite
K
 
2
ZrSi
 
3
O
 
9
·H
 
2
O
9.CJ.40Petarasite
Na
 
5
Zr
 
2
[(OH,Cl)|Si
 
6
O
 
18
]·2H
 
2
O
9.CJ.45Gerenite-(Y)
(Ca,Na)
 
2
(Y,REE)
 
3
Si
 
6
O
 
18
·2H
 
2
O
9.CJ.50Odintsovite
K
 
2
Na
 
4
Ca
 
3
Ti
 
2
Be
 
4
Si
 
12
O
 
38
9.CJ.55Mathewrogersite
Pb
 
7
(Fe
2+
 
,Cu)Al
 
3
Ge[(OH,H
 
2
O)
 
6
|(Si
 
3
O
 
9
)
 
4
]
Related Minerals - Hey's Index Grouping:
16.19.1Indialite
Mg
 
2
Al
 
4
Si
 
5
O
 
18
16.19.3Sekaninaite
(Fe,Mg)
 
2
Al
 
4
Si
 
5
O
 
18
16.19.4Ferrogedrite
☐[Fe
2+
2
][Fe
2+
3
Al
 
2
][(OH)
 
2
|Al
 
2
Si
 
6
O
 
22
]
16.19.5Staurolite
(Fe
2+
 
,Mg,Zn)
 
1.5-2
Al
 
9
[O
 
6
|(OH,O)
 
2
|(SiO
 
4
)
 
4
]
16.19.6Chloritoid
(Fe
2+
 
,Mg,Mn
2+
 
)Al
 
2
[O|(OH)
 
2
|SiO
 
4
]
16.19.7Amesite
Mg
 
2
Al[(OH)
 
4
|AlSiO
 
5
]
16.19.8Corundophilite
(Mg,Fe,Al)
 
6
(Si,Al)
 
4
O
 
10
(OH)
 
8
16.19.9Yoderite
Mg(Al,Fe
3+
 
)
 
3
[O|OH|(SiO
 
4
)
 
2
]
16.19.10Delessite
(Mg,Fe,Fe,Al)(Si,Al)
 
4
O
 
10
(O,OH)
 
8
16.19.11Ferrocarpholite
(Fe
2+
 
,Mg)Al
 
2
[(OH)
 
4
|Si
 
2
O
 
6
]
16.19.12Magnesiocarpholite
(Mg,Fe
2+
 
)Al
 
2
[(OH)
 
4
|Si
 
2
O
 
6
]
16.19.13Chamosite
(Fe
2+
 
,Mg)
 
5
Al[(OH)
 
8
|AlSi
 
3
O
 
10
]
16.19.14Orthochamosite
(Fe,Mg,Fe)
 
5
Al(Si
 
3
Al)O
 
10
(OH,O)
 
8
16.19.15Berthierine
(Fe,Fe,Mg)
 
2-3
(Si,Al)
 
2
O
 
5
(OH)
 
4
16.19.16Odinite
(Fe,Mg,Al,Fe,Ti,Mn)
 
2.4
(Si,Al)
 
2
O
 
5
(OH)
 
4
16.19.17Clinochlore
(Mg,Fe
2+
 
)
 
5
Al[(OH)
 
8
|AlSi
 
3
O
 
10
]
16.19.18Gedrite
☐[Mg
 
2
][Mg
 
3
Al
 
2
][(OH)
 
2
|Al
 
2
Si
 
6
O
 
22
]
16.19.19Magnesiogedrite
16.19.20Diabantite
(Mg,Fe,Al)
 
6
(Si,Al)
 
4
O
 
10
(OH)
 
8
16.19.21Sudoite
(Mg,Fe
2+
 
)
 
2
Al
 
3
[(OH)
 
8
|AlSi
 
3
O
 
10
]
16.19.22Vermiculite
(Mg,Fe,Al)
 
3
(Al,Si)
 
4
O
 
10
(OH)
 
2
·4H
 
2
O
16.19.23Corrensite
(Mg,Fe)
 
9
(Si,Al)
 
8
O
 
20
(OH)
 
10
·nH
 
2
O

Other Names for Cordierite

Synonyms:
DichroiteHard FahluniteIoliteJoliteLazulith (of von Schlotheim)
LuchsapphirLuchssaphirPeliomSpanish LazuliteSteinheilite
TanoliteWater Sapphire
German names:
CerasitCordieritDichroitIolitJolit
Lazulith (of van Schlotheim)Steinheilit
Japanese names:
菫青石
Russian names:
Кордиерит
Spanish names:
CerasitaCordieritaDichroitaIolitaJolita
Steinheilita
Traditional Chinese names:
蓳青石
Varieties:
Cerasite (of Kikuchi)

Other Information

Health Warning:No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Cordierite

Reference List:Venkatesh, V. (1952) Development and growth of cordierite in para-lavas. American Mineralogist: 37: 831-847.

Miyashiro, A., T. Iiyama, M. Yamasaki, and T. Miyashiro (1955) The polymorphism of cordierite and indialite. American Journal of Science: 253: 185-208.

Richet, P. and Bottinga, Y. (1984) Anorthite, andesine, wollastonite, diopside, cordierite, and pyrope thermodynamics of melting, glass transitions, and properties of the amorphous phases. Earth and Planetary Science Letters: 67: 415-432.

Putnis, A., Fyfe, C.A., and Gobbi, G.C. (1985) Aluminum-silicon ordering in cordierite using "magic angle spinning" NMR. I. Silicon-29 spectra of synthetic cordierite. Physics and Chemistry of Minerals: 12: 211-216.

Putnis, A. and Angel, R.J. (1985) Aluminum-silicon ordering in cordierite using "magic angle spinning" NMR. II: models of aluminum-silicon order from NMR data. Physics and Chemistry of Minerals: 12: 217-222.

American Mineralogist (1986): 71: 746-757.

Putnis, A., Salje, E., Redfern, S.A.T., Fyfe, C.A., and Strobl, H. (1987), Structural states of Mg-cordierite I: order parameters from synchrotron X-ray and NMR data. Physics and Chemistry of Minerals: 14: 446-454.

Schreyer, W., Maresch, W.V., Daniels, P., Wolfsdorff, P. (1990): Potassic cordierites: characteristic minerals for high-temparature, very low-pressure environmnets, Contributions to Mineralogy and Petrology, 105, 162-172.

Contributions to Mineralogy and Petrology: 140: 344-352.

Bertoldi, C., Proyer, A., Garbe-Schönberg, D., Behrens, ., and Dachs, E. (2004) Comprehensive chemical analyses of natural cordierites: implications for exchange mechanisms. Lithos: 78: 389-409.

Yakubovich, O. V., Massa, V., Pekov, I. V., Gavrilenko, P. G. & Chukanov, N. V. (2004): Crystal structure of the Na-, Ca-, Be-cordierite and crystallochemical regularities in the cordierite-sekaninaite series. Crystallography Reports 49, 953-963.

Internet Links for Cordierite

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    Localities for Cordierite

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