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Sillimanite

Big Photo

Ratnapura, Sabaragamuwa Province, Sri Lanka
© Rob Lavinsky

Show Sillimanite Photos (46)
Formula:
Al
 
2
[O|SiO
 
4
]
System:OrthorhombicColour:Colourless, white, ...
Hardness:6½ - 7½
Name:
Named after Benjamin Silliman (1779-1864), Professor of Chemistry and Geology, Yale University, New Haven, Connecticut, USA, and founder of the American Journal of Science (Silliman's Journal).
Polymorph of:Andalusite, Kyanite


Sillimanite Group

Classification of Sillimanite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:8/B.02-10
Nickel-Strunz 10th (pending) edition ID:9.AF.05

9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination
Dana 8th edition ID:52.2.2a.1

52 : NESOSILICATES Insular SiO4 Groups and O,OH,F,H2O
2 : Insular SiO4 Groups and O, OH, F, and H2O with cations in [4] and >[4] coordination
Hey's CIM Ref.:15.3

15 : Silicates of Aluminum
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Type Occurrence of Sillimanite

Type Locality:Chester, Middlesex Co., Connecticut, USA
Year of Discovery:1824

Physical Properties of Sillimanite

Lustre:Vitreous, Silky
Diaphaneity (Transparency):Transparent, Translucent
Colour:Colourless, white, yellow, brown, green, gray.
Hardness (Mohs):6½ - 7½

Crystallography of Sillimanite

Crystal System:Orthorhombic
Cell Parameters:a = 7.47Å, b = 7.66Å, c = 5.75Å
Ratio:a:b:c = 0.975 : 1 : 0.751
Unit Cell Volume:V 329.02 ų (Calculated from Unit Cell)
X-Ray Powder Diffraction:
Image Loading

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 Sillimanite

Type:Biaxial (+)
RI values: nα = 1.653 - 1.661 nβ = 1.654 - 1.670 nγ = 1.669 - 1.684
2V:Measured: 20° to 30°, Calculated: 30° to 80°
Maximum Birefringence:δ = 0.016 - 0.023

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate
Dispersion:strong

Chemical Properties of Sillimanite

Formula:
Al
 
2
[O|SiO
 
4
]
Essential elements:Al, O, Si
All elements listed in formula:Al, O, Si
Common Impurities:Fe

Relationship of Sillimanite to other Species

Related to:
  • Sillimanite Group
    • Related Minerals - Nickel-Strunz Grouping):

    - +
    9.AF.10Andalusite
    Al
     
    2
    		[O|SiO
     
    4
    		]
    9.AF.10Kanonaite
    Mn
    3+
     
    		Al[O|SiO
     
    4
    		]
    9.AF.15Kyanite
    Al
     
    2
    		[O|SiO
     
    4
    		]
    9.AF.20Mullite
    Al
     
    8
    		[(O,OH,F)|(Si,Al)O
     
    4
    		]
     
    4
    9.AF.20Krieselite
    (Al,Ga)
     
    2
    		[(OH)
     
    2
    		|GeO
     
    4
    		]
    9.AF.23Boromullite
    Al
     
    9
    		Si
     
    2
    		BO
     
    19
    9.AF.25Yoderite
    Mg(Al,Fe
    3+
     
    		)
     
    3
    		[O|OH|(SiO
     
    4
    		)
     
    2
    		]
    9.AF.30Magnesiostaurolite
    (Mg,Li,Fe
    2+
     
    		)
     
    1.5-2
    		Al
     
    9
    		[O
     
    6
    		|(OH)
     
    2
    		|(SiO
     
    4
    		)
     
    4
    		]
    9.AF.30Staurolite
    (Fe
    2+
     
    		,Mg,Zn)
     
    1.5-2
    		Al
     
    9
    		[O
     
    6
    		|(OH,O)
     
    2
    		|(SiO
     
    4
    		)
     
    4
    		]
    9.AF.30Zincostaurolite
    (Zn,Li,Fe
    2+
     
    		,Mg)
     
    <2
    		Al
     
    9
    		[O
     
    6
    		|(OH)
     
    2
    		|(SiO
     
    4
    		)
     
    4
    		]
    9.AF.35Topaz
    Al
     
    2
    		[(F,OH)
     
    2
    		|SiO
     
    4
    		]
    9.AF.40Norbergite
    Mg
     
    3
    		[(F,OH)
     
    2
    		|SiO
     
    4
    		]
    9.AF.45Alleghanyite
    Mn
    2+
    5
    		[(OH)
     
    2
    		|(SiO
     
    4
    		)
     
    2
    		]
    9.AF.45Chondrodite
    (Mg,Fe
    2+
     
    		)
     
    5
    		[(F,OH)
     
    2
    		|(SiO
     
    4
    		)
     
    2
    		]
    9.AF.45Reinhardbraunsite
    Ca
     
    5
    		[(OH,F)
     
    2
    		|(SiO
     
    4
    		)
     
    2
    		]
    9.AF.45IMA2008-045
    Ca
     
    5
    		(SiO
     
    4
    		)
     
    2
    		F
     
    2
    9.AF.50Humite
    (Mg,Fe
    2+
     
    		)
     
    7
    		[(F,OH)
     
    2
    		|(SiO
     
    4
    		)
     
    3
    		]
    9.AF.50Manganhumite
    (Mn
    2+
     
    		,Mg)
     
    7
    		[(OH)
     
    2
    		|(SiO
     
    4
    		)
     
    3
    		]
    9.AF.55Clinohumite
    (Mg,Fe
    2+
     
    		)
     
    9
    		[(F,OH)
     
    2
    		|(SiO
     
    4
    		)
     
    4
    		]
    9.AF.55Sonolite
    Mn
    2+
    9
    		[(OH,F)
     
    2
    		|(SiO
     
    4
    		)
     
    4
    		]
    9.AF.55Hydroxylclinohumite
    Mg
     
    9
    		[(OH,F)
     
    2
    		|(SiO
     
    4
    		)
     
    4
    		]
    9.AF.60Leucophoenicite
    Mn
    2+
    7
    		[(OH)
     
    2
    		|(SiO
     
    4
    		)
     
    3
    		]
    9.AF.65Ribbeite
    (Mn
    2+
     
    		,Mg)
     
    5
    		[(OH)
     
    2
    		|(SiO
     
    4
    		)
     
    2
    		]
    9.AF.70Jerrygibbsite
    Mn
    2+
    9
    		[(OH)
     
    2
    		|(SiO
     
    4
    		)
     
    4
    		]
    9.AF.75Franciscanite
    Mn
    2+
    6
    		(V
    5+
     
    		,[])
     
    2
    		[(O,OH)
     
    3
    		|SiO
     
    4
    		]
     
    2
    9.AF.75Örebroite
    Mn
    2+
    3
    		(Fe
    3+
     
    		,Sb
    5+
     
    		)[(O,OH)
     
    3
    		|SiO
     
    4
    		]
    9.AF.75Welinite
    Mn
    2+
    6
    		(W
    6+
     
    		,Mg)
     
    2
    		[(O,OH)
     
    3
    		|SiO
     
    4
    		]
     
    2
    9.AF.80Ellenbergerite
    Mg
     
    6
    		Al
     
    6
    		Ti[(OH)
     
    6
    		|(HSiO
     
    4
    		)
     
    4
    		|(SiO
     
    4
    		)
     
    4
    		]
    9.AF.85Chloritoid
    (Fe
    2+
     
    		,Mg,Mn
    2+
     
    		)Al
     
    2
    		[O|(OH)
     
    2
    		|SiO
     
    4
    		]
    9.AF.85Magnesiochloritoid
    MgAl
     
    2
    		[O|(OH)
     
    2
    		|SiO
     
    4
    		]
    9.AF.85Ottrélite
    (Mn
    2+
     
    		,Fe
    2+
     
    		,Mg)Al
     
    2
    		[O|(OH)
     
    2
    		|SiO
     
    4
    		]
    9.AF.90Poldervaartite
    CaCa[SiO
     
    3
    		OH](OH)
    9.AF.90Olmiite
    CaMn
    2+
     
    		[SiO
     
    3
    		(OH)](OH)
    Related Minerals - Hey's Index Grouping:

    - +
    15.1Andalusite
    Al
     
    2
    		[O|SiO
     
    4
    		]
    15.2Kyanite
    Al
     
    2
    		[O|SiO
     
    4
    		]
    15.4Mullite
    Al
     
    8
    		[(O,OH,F)|(Si,Al)O
     
    4
    		]
     
    4
    15.5Pyrophyllite
    Al
     
    2
    		Si
     
    4
    		O
     
    10
    		(OH)
     
    2
    15.6Dickite
    Al
     
    2
    		Si
     
    2
    		O
     
    5
    		(OH)
     
    4
    15.7Nacrite
    Al
     
    2
    		Si
     
    2
    		O
     
    5
    		(OH)
     
    4
    15.8Kaolinite
    Al
     
    2
    		Si
     
    2
    		O
     
    5
    		(OH)
     
    4
    15.9Metahalloysite
    15.10Halloysite
    Al
     
    2
    		Si
     
    2
    		O
     
    5
    		(OH)
     
    4
    15.11Allophane
    (Al
     
    2
    		O
     
    3
    		)(SiO
     
    2
    		)
     
    1.3-2
    		·2.5-3H
     
    2
    		O

    Other Names for Sillimanite

    Synonyms:
    Bournonite (of Lucas)BucholziteFaserkiesel (of Lindacker)FibroliteFribolite
    MonroeliteMonroliteSelmanite
    Other Languages:
    Croatian:Sillimanit
    Dutch:Sillimaniet
    Finnish:Andalusiitti
    French:Sillimanite
    German:Sillimanit
    Bucholzit
    Fibrolit
    Fibrolith
    Glanzspat
    Monrolit
    Hebrew:סילימניט
    Hungarian:Szillimanit
    Italian:Sillimanite
    Japanese:珪線石
    Polish:Sillimanit
    Russian:Силлиманит
    Simplified Chinese:矽線石
    Spanish:Sillimanita
    Bucholzita
    Fibrolita
    Monrolita
    Swedish:Sillimanit

    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 Sillimanite

    Reference List:Bowen G.T. (1824), American Journal of Science, 8, 113.

    Clark, S.P., E.C. Robertson & F. Birch (1957), Experimental determination of kyanite-sillimanite equilibrium relations at high temperatures and pressure: American Journal of Science: 255: 628-640.

    Pearson, G.R. and Shaw, D.M. (1960) Trace elements in kyanite, sillimanite and andalusite. American Mineralogist: 45: 808-817.

    Burnham, C.W. (1963a) Refinement of the crystal structure of sillimanite. Zeitschrift für Kristollographie: 118: 127-148.

    Chinner, G.A., J.W. Smith & C.R. Knowles (1969), Transition metal contents of Al2SiO5 polymorphs: American Journal of Science: 267A: 96-113.

    Raymond, M. and Hafner, S.S. (1970) Nuclear quadrupole coupling tensors of 27 Al in sillimanite Al2SiO5). Journal of Chemical Physics: 53: 4110-4111.

    Finger, L.W. and Prince, E. (1972) Neutron diffraction studies: andalusite and sillimanite. Carnegie Institution of Washington, Year Book: 71: 496-500.

    Vaughan, M.T. and Weidner, D.J. (1978) The relationship of elasticity and crystal structure in andalusite and sillimanite. Physics and Chemistry of Minerals: 3: 133-144.

    Vernon, R.H. (1979) Formation of late sillimanite by hydrogen metasomatism (base-leaching) in some high-grade gneisses. Lithos: 12: 143-152.

    Winter, J.K. and Ghose, S. (1979) Thermal expansion and high-temperature crystal chemistry of the Al2SiO5 polymorphs. American Mineralogist: 64: 573-586.

    Grew, E.S. (1980a) Sillimanite and ilmenite from high grade metamorphic rocks of Antarctica and other areas. Journal of Petrology: 21: 39-68.

    Fleet, M.E. and Arima, M. (1985) Oriented hematite inclusions in sillimanite. American Mineralogist: 70: 1232-1237.

    Grew, E.S. and Rossman, G.R. (1985) Co-ordination of boron in sillimanite. Mineralogical Magazine: 49: 132-135.

    Vernon, R.H., Flood, R.H., and D'Arcy, W.F. (1987) Sillimanite and andalusite produced by base-cation leaching and contact metamorphism of felsic igneous rocks. Journal of Metamorphic Geology: 5: 439-450.

    Kerrick, D.M. (1990) Metamorphic reactions. In D.M. Kerrick, Ed., The Al2SiO5 polymorphs. 22, 223-253. Reviews in Mineralogy. Mineralogical Society of America, Chantilly, Virginia.

    Kerrick, D.M. (1990) The Al2SiO5 polymorphs, 22, 406 p. Reviews in Mineralogy, Mineralogical Society of America, Chantilly, Virginia.

    American Mineralogist (1992): 77: 374.

    Yang, H., Hazen, R.M., Finger, L.W., Prewitt, C.T., and Downs, R.T. (1997b) Compressibility and crystal structure of sillimanite, Al2SiO5, at high pressure. Physics and Chemistry of Minerals: 25: 39-47.

    Rao, M.N., Chaplot, S.L., Choudhury, N., Rao, K.R., Azuah, R.T., Montfrooji, W.T., and Bennington, S.M. (1999) Lattice dynamics and inelastic neutron scattering from sillimanite and kyanite Al2SiO5. Physical Review: B60: 12061.

    Dahaoui, S., Ghermani, N.E., Ghose, S., and Howard, J.A.K. (2001) Electric field gradient tensors at the aluminum sites in the Al2SiO5 polymorphs from CCD high resolution X-ray diffraction data: comparison with 27 Al NMR results. American Mineralogist: 86: 159-164.

    Iglesias, M., Schwarz, K., Blaha, P., and Baldomir, D. (2001) Electronic structure and electric field gradient calculations of Al2SiO5 polymorphs. Physics and Chemistry of Minerals: 28: 67-75.

    Winkler, B., Hytha, M., Warren, M.C., Milman, V., Gale, J.D., and Schreuer, J. (2001) Calculation of the elastic constants of the Al2SiO5 olymorphs andalusite, sillimanite, and kyanite. Zeitschrift für Kristallographie: 216: 67-70.

    Friedrich, A., Kunz, M., Winkler, B., and Le Bihan T. (2004) High-pressure beahvior of sillimanite and kyanite: compressibility, decomposition and indications of a new high-pressure phase. Zeitschrift für Kristallographie: 219: 324-329.

    Burt, J.B., Ross, N.L., Angel, R.J., and Koch, M. (2006) Equations of state and structures of andalusite to 9.8 GPa and sillimanite to 8.5 GPa. American Mineralogist: 91: 319-326.

    Ohuchi, F.S., Ghose, S., Engelhard, M.H., and Baer, D.R. (2006) Chemical bonding and electronic structures of the Al2SiO5 polymorphs, andalusite, sillimanite, and kyanite: X-ray photoelectron- and electron energy loss spectroscopy studies. American Mineralogist: 91: 740-746.

    Internet Links for Sillimanite

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  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Search for Sillimanite in the Natural History Museum (London) online catalogue
  • Sillimanite details from Handbook of Mineralogy (PDF)
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    Localities for Sillimanite

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