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Mullite

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Big Photo

Caspar quarry, Bellerberg volcano, Ettringen, Mayen, Eifel Mts, Rhineland-Palatinate, Germany
© Stephan Wolfsried

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Formula:
Al
 
4+2x
Si
 
2-2x
O
 
10-x
(x ~ 0.4)
System:OrthorhombicColour:Colourless, white, ...
Hardness:6 - 7
Name:After the discovery locality, the Isle of Mull, Scotland.


Synthetic mullite is well-known as a high-performance ceramic.

Classification of Mullite

IMA status:Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
Strunz 8th edition ID:8/B.02-50
Nickel-Strunz 10th (pending) edition ID:9.AF.20

9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination
Dana 8th edition ID:52.2.3.1

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.:15.4

15 : Silicates of Aluminum
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Type Occurrence of Mullite

Type Locality:Seabank Villa, Isle of Mull, Strathclyde (Argyllshire), Scotland, UK
Year of Discovery:1924

Physical Properties of Mullite

Lustre:Vitreous
Diaphaneity (Transparency):Transparent, Translucent
Colour:Colourless, white, yellow, pink, red, gray
Hardness (Mohs):6 - 7
Cleavage:Distinct/Good
Distinct on {010}
Density (measured):3.11 - 3.26 g/cm3
Density (calculated):3.17 g/cm3

Crystallography of Mullite

Crystal System:Orthorhombic
Class (H-M):mmm (2/m 2/m 2/m) - Dipyramidal
Space Group:Pbam {P21/b 21/a 2/m}
Cell Parameters:a = 7.5785(6) Å, b = 7.6817(7) Å, c = 2.8864(3) Å
Ratio:a:b:c = 0.987 : 1 : 0.376
Unit Cell Volume:V 168.03 ų (Calculated from Unit Cell)
Z:1
Morphology:Crystals prismatic to acicular
Comment:On synthetic material.
X-Ray Powder Diffraction:
d-spacingIntensity
5.39 (50)
3.390 (100)
3.428 (95)
2.694 (40)
2.542 (50)
2.206 (60)
1.5242 (35)
Comments:For synthetic material.

Optical Data of Mullite

Type:Biaxial (+)
RI values: nα = 1.642 - 1.653 nβ = 1.644 - 1.655 nγ = 1.654 - 1.679
2V:Measured: 20° to 50°, Calculated: 34° to 50°
Maximum Birefringence:δ = 0.012 - 0.026

Chart shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:Moderate
Dispersion:r > v
Pleochroism:Visible
Comments:X=Y= colorless
Z= rose-pink

Chemical Properties of Mullite

Formula:
Al
 
4+2x
Si
 
2-2x
O
 
10-x


(x ~ 0.4)
Essential elements:Al, O, Si
All elements listed in formula:Al, O, Si
Common Impurities:Ti,Fe,Na,K

Relationship of Mullite to other Species

Related Minerals - Nickel-Strunz Grouping):

- +
9.AF.05Sillimanite
Al
 
2
(SiO
 
4
)O
9.AF.10Andalusite
Al
 
2
(SiO
 
4
)O
9.AF.10Kanonaite
Mn
3+
 
Al(SiO
 
4
)O
9.AF.15Kyanite
Al
 
2
(SiO
 
4
)O
9.AF.20Krieselite
(Al,Ga)
 
2
(GeO
 
4
)(OH)
 
2
9.AF.23Boromullite
Al
 
9
BSi
 
2
O
 
19
9.AF.25Yoderite
Mg(Al,Fe
3+
 
)
 
3
(SiO
 
4
)
 
2
O(OH)
9.AF.30Magnesiostaurolite
(Mg,Li,Fe
2+
 
)
 
1.5-2
Al
 
9
(SiO
 
4
)
 
4
O
 
6
(OH)
 
2
9.AF.30Staurolite
(Fe
2+
 
,Mg,Zn)
 
1.5-2
Al
 
9
(SiO
 
4
)
 
4
O
 
6
(OH,O)
 
2
9.AF.30Zincostaurolite
(Zn,Li,Fe
2+
 
,Mg)
 
1.5-2
Al
 
9
(SiO
 
4
)
 
4
O
 
6
(OH)
 
2
9.AF.35Topaz
Al
 
2
(SiO
 
4
)(F,OH)
 
2
9.AF.40Norbergite
Mg
 
3
(SiO
 
4
)(F,OH)
 
2
9.AF.45Alleghanyite
Mn
2+
5
(SiO
 
4
)
 
2
(OH)
 
2
9.AF.45Chondrodite
(Mg,Fe
2+
 
)
 
5
(SiO
 
4
)
 
2
(F,OH)
 
2
9.AF.45Reinhardbraunsite
Ca
 
5
(SiO
 
4
)
 
2
(OH,F)
 
2
9.AF.45Kumtyubeite
Ca
 
5
(SiO
 
4
)
 
2
F
 
2
9.AF.45Hydroxylchondrodite
Mg
 
5
(SiO
 
4
)
 
2
(OH)
 
2
9.AF.50Humite
(Mg,Fe
2+
 
)
 
7
(SiO
 
4
)
 
3
(F,OH)
 
2
9.AF.50Manganhumite
(Mn
2+
 
,Mg)
 
7
(SiO
 
4
)
 
3
(OH)
 
2
9.AF.50Unnamed (Ca-analogue of Humite)
Ca
 
7
(SiO
 
4
)
 
4
F
 
2
9.AF.55Clinohumite
(Mg,Fe
2+
 
)
 
9
(SiO
 
4
)
 
4
(F,OH)
 
2
9.AF.55Sonolite
Mn
2+
9
(SiO
 
4
)
 
4
(OH,F)
 
2
9.AF.55Hydroxylclinohumite
Mg
 
9
(SiO
 
4
)
 
4
(OH,F)
 
2
9.AF.60Leucophoenicite
Mn
2+
7
(SiO
 
4
)
 
3
(OH)
 
2
9.AF.65Ribbeite
(Mn
2+
 
,Mg)
 
5
(SiO
 
4
)
 
2
(OH)
 
2
9.AF.70Jerrygibbsite
Mn
2+
9
(SiO
 
4
)
 
4
(OH)
 
2
9.AF.75Franciscanite
Mn
2+
6
(V
5+
 
,☐)
 
2
(SiO
 
4
)
 
2
(O,OH)
 
6
9.AF.75Örebroite
Mn
2+
3
(Fe
3+
 
,Sb
5+
 
)(SiO
 
4
)(O,OH)
 
3
9.AF.75Welinite
Mn
2+
6
(W
6+
 
,Mg)
 
2
(SiO
 
4
)
 
2
(O,OH)
 
6
9.AF.80Ellenbergerite
Mg
 
6
(Mg,Ti,Zr,◻)
 
2
(Al,Mg)
 
6
Si
 
8
O
 
28
(OH)
 
10
9.AF.85Chloritoid
(Fe
2+
 
,Mg,Mn
2+
 
)Al
 
2
(SiO
 
4
)O(OH)
 
2
9.AF.85Magnesiochloritoid
MgAl
 
2
(SiO
 
4
)O(OH)
 
2
9.AF.85Ottrélite
(Mn
2+
 
,Fe
2+
 
,Mg)Al
 
2
(SiO
 
4
)O(OH)
 
2
9.AF.90Poldervaartite
CaCa(HSiO
 
4
)(OH)
9.AF.90Olmiite
CaMn
2+
 
(HSiO
 
4
)(OH)
Related Minerals - Hey's Index Grouping:

- +
15.1Andalusite
Al
 
2
(SiO
 
4
)O
15.2Kyanite
Al
 
2
(SiO
 
4
)O
15.3Sillimanite
Al
 
2
(SiO
 
4
)O
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 Mullite

Synonyms:
Keramite (of Mellor and Scott)
Other Languages:
German:Mullit
Porcelainit
Russian:Муллит
Simplified Chinese:莫来石
Spanish:Mullita
Porcelainita

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 Mullite

Reference List:

- +
American Mineralogist (1924): 9: 211.

Brindley, G.W. and Nakahira, M. (1959) The kaolinite-mullite reaction series: I, Survey of outstanding problems. II, Metakaolin. III, The high-temperature phases. Journal of the American Ceramic Society: 42: 311-324.

Ernst, W.G. & S.E. Calvert (1969), An experimental study of the recrystallization of porcelanite and its bearing on the origin of some bedded cherts: American Journal of Science: 267A: 114-133.

Cameron, W.E. (1977) Mullite: a substituted alumina. American Mineralogist: 62: 747-755.

Leonard, A.J. (1977) Structural analysis of the transition phases in the kaolinite-mullite thermal sequence. Journal of the American Ceramic Society: 60: 37-43.

Angel, R.J., and Prewitt, C.T. (1986): Crystal structure of mullite: A re-examination of the average structure. American Mineralogist 71, 1476-1482.

Srikrisna, K., Thomas, G., Martinez, R., Corral, M.P., de Aza, S., and Moya, J.S. (1990) Kaolinite-mullite reaction series: a TEM study. Journal of Materials Science: 25: 607-612.

American Mineralogist (1991): 76: 332.

Lee, S., Kim, Y.J., and Moon, H.S. (1999) Phase transformation sequence from kaolinite to mullite investigated by an energy-filtering transmission electron microscope. Journal of the American Ceramic Society: 82: 2841-2848.

Voll, D., Angerer, P., Beran, A., and Schneider, H. (2002) A new assignment of IR vibrational modes in mullite. Vibrational Spectroscopy: 30: 237-243.

Rodriguez-Navarro, C., Cultrone, G., Sanchez-Navas, A., and Sbastian, E. (2003) TEM study of mullite growth after muscovite breakdown. American Mineralogist: 88: 713-724.

Internet Links for Mullite

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  • Raman and XRD data at RRUFF project
  • American Mineralogist Crystal Structure Database
  • Mullite details from Handbook of Mineralogy (PDF)
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    • Localities for Mullite

    The map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
    Hide Locality List
    (TL) indicates type locality. ? indicates mineral may be doubtful at this locality. All other localities listed without reference should be considered as uncertain and unproven until references can be found.
    Austria
     
    • Burgenland
      • Oberpullendorf
        • Kobersdorf
          • Pauliberg Mt.
    		U. Kolitsch, W. Postl, H.-P. Bojar and W. Trattner (2009): Die Mineralvorkommen im Basalt des Pauliberges. In: Autorenkollektiv (Red. M. A. Götzinger und P. Huber) (2009): Die Mineralien des Burgenlandes - Geologie, Mineralogie und mineralische Rohstoffe. – Wissenschaftliche Arbeiten aus dem Burgenland, Band 126, Amt der Burgenländischen Landesregierung, Abteilung 7 - Landesmuseum, Eisenstadt, 83-99.
    China
     
    Guangce Zeng, Baoming Pan, and Shangyue Shen (1993): Acta Mineralogica Sinica 13(1), 84-86
    • Shanxi Province
      • Yangquan Prefecture
        • Kuang District
    		- Querol, X.; Izquierdo, M.; Monfort, E.; Alvarez, E.; Font, O.; Moreno, T.; Alastuey, A.; Zhuang, X.; Lu, W.; Wang, Y. (2008): Environmental characterization of burnt coal gangue banks at Yangquan, Shanxi Province, China. International Journal of Coal Geology 75, 93-104.
    Czech Republic
     
    • Bohemia (Böhmen; Boehmen)
      • Central Bohemia Region
    		Zacek, V., Oplustil, S., Mayova, A. & Meyer, F. R. (1995): Die Mineralien von Kladno in Mittelböhmen, Tschechische Republik. Mineralien-Welt 6 (1), 13-30 (in German).
          • Libušin
    		David Parfitt collection
      • Hradec Králové Region
        • Trutnov (Trautenau)
          • Radvanice
    		Jirásek, J.: Thermal Changes of the Rocks in the Dump Pile of the Kateřina Colliery in Radvanice (Eastern Bohemia). Ostrava: VSB – Technical University of Ostrava, Institute of Geological Engineering - 541, 2001. 69 p.
      • Ústí Region
        • Most
    		Ferry FEDIUK, Anna LANGROVÁ and Karel MELKA. 2003. "North Bohemian Porcellanites and their Mineral Composition: the Case of the Dobrčice Quarry, the Most Basin" GeoLines 15, p. 35-43. PDF: http://geolines.gli.cas.cz/fileadmin/volumes/volume15/G15-035.pdf
    France
     
    • Auvergne
      • Haute-Loire
        • Le Puy-en-Velay
          • Espaly-Saint-Marcel
    		D. BARRIER, G. POURTIER & P. MEDARD, 2004, Minéralogie du Mont Denise (Haute-Loire), Le Cahier des Micromonteurs, 83, pp 3-8
    Germany
     
    • Bavaria
      • Franconia
        • Fichtelgebirge
          • Marktredwitz
            • Pechbrunn
    		Weiss: "Mineralfundstellen, Deutschland West", 1990
      • Upper Palatinate
        • Kemnath
          • Waldeck
    		Pöllmann et al. (2007): Aufschluss 58, 227-233.
        • Oberpfälzer Wald
          • Mitterteich
            • Wiesau
    		Weiss: "Mineralfundstellen, Deutschland West", 1990
    • Hesse
      • Cornberg
    		Müller, G. (1967): Contributions to Mineralogy and Petrology 14, 176-189.
    • Rhineland-Palatinate
      • Eifel Mts
        • Andernach
          • Eich
    		Hentschel, G., Die Mineralien der Eifelvulkane, Weise Verlag München, 1983
          • Nickenich
    		Hentschel, G., Die Mineralien der Eifelvulkane, Weise Verlag München, 1983
        • Daun
          • Oberstadtfeld
    		Leu, K., Der Vulkanabbau "Auf´m Kopp" bei Oberstadtfeld in der Westeifel, Lapis 2/1995
          • Üdersdorf
    		Schäfer, H., Die Mineralien der Einschlüsse und Auswürflinge in den Schlacken des Emmelberges bei Üdersdorf / Eifel, Der Aufschluss 30, 273-282, 1979
    Guth, G., Interessante Neufunde für den Basaltbruch Liley (Löley) bei Üdersdorf in der Westeifel Mineralien-Welt 2/2000
        • Kelberg
          • Drees
    		Schüller, W., Die Mineralien des Niveligsberges bei Drees in der Eifel, Der Aufschluß SB 33, 1990
        • Laach lake volcanic complex
          • Kruft
    		Blass, G.; Graf, H.W., Neufunde von bekannten Fundorten (X), Mineralien-Welt 5/2, 43, 1994
          • Mendig
            • Niedermendig
    		Blass, G.; Graf, H.W., Neufunde von bekannten Fundorten (X), Mineralien-Welt 5/2, 43, 1994
    Blass, G.; Graf, H.W., Neufunde von bekannten Fundorten (X), Mineralien-Welt 5/2, 43, 1994
              • Wingertsberg Mt.
    		Blass, G.; Graf, H.W., Neufunde von bekannten Fundorten (X), Mineralien-Welt 5/2, 43, 1994
        • Mayen
          • Ettringen
            • Bellerberg volcano
    		Hentschel, G., Neufunde seltener Minerale im Laacher Vulkangebiet, Aufschluß 28, 129-133, 1977
        • Mendig
          • Bell
    		Hentschel, G., Die Mineralien der Eifelvulkane, Weise Verlag München, 1983
        • Niederzissen
          • Burgbrohl
    		Hentschel, G., Die Mineralien der Eifelvulkane, Weise Verlag München, 1983
        • Polch
          • Ochtendung
    		Lapis 1988(7+8), 70-72
    • Saxony
      • Zwickau
        • Oelsnitz
    		T. Witzke (1996): Die Minerale der brennenden Halde der Steinkohlengrube "Deutschland-schacht" in Oelsnitz bei Zwickau.- Aufschluss 47, 41-48
    • Thuringia
      • Gera
        • Ronneburg U deposit
    		T. Witzke & F. Rüger: Lapis 1998(7/8), 26-64
    Hungary
     
    • Vas Co.
      • Kemeneshát
        • Celldömölk
    		Szakáll & Gatter. Hun. Min. Spec., 1993
    Italy
     
    • Campania
      • Naples Province
        • Somma-Vesuvius Complex
          • Monte Somma
            • Ercolano
    		D. Preite collection
    • Sardinia
      • Oristano Province
        • Mt. Arci
          • Marrubiu
    		Roberto Bosi collection
    Bortolozi G. (1986) - Mullite e Pseudobrookite del M. Arci (Or) - Riv. Mineral. Ital. , Milano, Fasc. 3, pag. 136
    Japan
     
    • Honshu Island
      • Chubu region
        • Nagano prefecture
    		Matsubara et al (1998) Ganko-Gakkai Kou'en-Youshi, 34.
    Netherlands
     
    • Limburg
      • Kerkrade
    New Zealand
     
    • North Island
      • Bay of Plenty
        • Rotorua
          • Mt. Ngongotaha
    		Martin Stolworthy Collection
      • Lake Taupo
    		Thornton, J. (Ed.), The Micro-Scope, No. 41, February 2002
      • Taupo
        • Atiamuri
    		Personal collection of Rod Martin
    Poland
     
    • Upper Silesia (Śląskie)
      • Upper Silesian Coal Basin
        • Katowice area
          • Łaziska
    		Lukasz Kruszewski 2005: Minerals arising in cause of underground fires of "Skalny" coal mine dump in Laziska, Upper Silesia.Mag. Thesis (unpublished)
    Russia
     
    • Urals Region
      • Southern Urals
        • Chelyabinsk Oblast'
    		Cesnokov, B., Kotrly, M. and Nisanbajev, T. (1998): Brennende Abraumhalden und Aufschlüsse im Tscheljabinsker Kohlenbecken - eine reiche Mineralienküche. Mineralien-Welt, 9 (3), 54-63 (in German).
    No reference listed
    Slovakia
     
    • Košice Region
      • Michalovce Co.
    		Bacsó,Z.,Ďuďa,R.,1988: Metalogenéza a rudné formácie rudného poľa Remetské Hámre. Min.Slovaca,Bratislava, 3, 193-220p
        • Remetské Hámre
    		[Eur.J.Mineral. 13:177-186]
    South Africa
     
    • Free State Province
      • Boshof
    		Mathias, M., Siebert, J.C., and Rickwood, P.C. (1970): Contributions to Mineralogy and Petrology 26, 75-123.
    Spain
     
    • Andalusia
      • Almería
    		Robert A. Jenkins
    Tajikistan
     
    • Viloyati Sogd (Viloyati Sughd; Viloyati Khodzhent; Viloyati Leninabad)
      • Zeravshan Range
        • Yagnob River
    		Sharygin, V.V., Sokol, E.V. and Belakovskii, D.I. (2009): Fayalite-sekaninaite paralava from the Ravat coal fire (central Tajikistan). Russian Geology and Geophysics 50, 703-721.
    UK
     
    • Scotland
      • Strathclyde (Argyllshire)
        • Isle of Mull
    		No reference listed
    BMS Database
    N L. Bowen, J W. Greig and E G. Zies. Mullite, a silicate of alumina. Jour Wash. Acad. Sci., 14, 183, 1924.
    BMS Database; Am Min 50:1982-2022
    USA
     
    • Idaho
      • Shoshone Co.
        • Goat Mountain District
    		U.S. Geological Survey, 2005, Mineral Resources Data System: U.S. Geological Survey, Reston, Virginia.
    • New Jersey
      • Middlesex Co.
    		AmMin 10:152-155
    Mineral and/or Locality
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