Mullite
A valid IMA mineral species - grandfathered
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About Mullite
Seabank Villa, Isle of Mull.
Seabank Villa, Loch Scridain, Isle of Mull, Argyll and Bute, Scotland, UK
Seabank Villa, Loch Scridain, Isle of Mull, Argyll and Bute, Scotland, UK
Formula:
Al4+2xSi2-2xO10-x
(x ~ 0.4)
Colour:
Colourless, white, yellow, pink, red, gray
Lustre:
Vitreous
Hardness:
6 - 7
Specific Gravity:
3.11 - 3.26
Crystal System:
Orthorhombic
Name:
Named after the discovery locality, the Isle of Mull, Scotland.
Synthetic mullite is well-known as a high-performance ceramic.
Compare 'meta-kaolinite', 'pseudomullite', and 'silicon spinel' - synthetic phases being intermediate products of mullite formation from kaolinite.
Compare 'meta-kaolinite', 'pseudomullite', and 'silicon spinel' - synthetic phases being intermediate products of mullite formation from kaolinite.
Unique Identifiers
Mindat ID:
2806
Long-form identifier:
mindat:1:1:2806:2
GUID
(UUID V4):
(UUID V4):
217e94ed-8d2c-402d-8b1a-0b40f1fc2b62
IMA Classification of Mullite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Al4+2xSi2-2xO10-x (x ≈ 0.4)
First published:
1924
Classification of Mullite
9.AF.20
9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination
9 : SILICATES (Germanates)
A : Nesosilicates
F : Nesosilicates with additional anions; cations in [4], [5] and/or only [6] coordination
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
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
15.4
15 : Silicates of Aluminum
15 : Silicates of Aluminum
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference |
|---|---|---|
| Mul | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Mul | Kretz (1983) | Kretz, R. (1983) Symbols of rock-forming minerals. American Mineralogist, 68, 277–279. |
| Mul | Siivolam & Schmid (2007) | Siivolam, J. and Schmid, R. (2007) Recommendations by the IUGS Subcommission on the Systematics of Metamorphic Rocks: List of mineral abbreviations. Web-version 01.02.07. IUGS Commission on the Systematics in Petrology. download |
| Mul | Whitney & Evans (2010) | Whitney, D.L. and Evans, B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95, 185–187 doi:10.2138/am.2010.3371 |
| Mul | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Mullite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Colourless, white, yellow, pink, red, gray
Hardness:
6 - 7 on Mohs scale
Cleavage:
Distinct/Good
Distinct on {010}
Distinct on {010}
Density:
3.11 - 3.26 g/cm3 (Measured) 3.17 g/cm3 (Calculated)
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°
Max Birefringence:
δ = 0.012 - 0.026
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Moderate
Dispersion:
r > v
Pleochroism:
Visible
Comments:
X=Y= colorless
Z= rose-pink
Z= rose-pink
Chemistry of Mullite
Mindat Formula:
Al4+2xSi2-2xO10-x
(x ~ 0.4)
(x ~ 0.4)
Elements listed:
Common Impurities:
Ti,Fe,Na,K
Crystallography of Mullite
Crystal System:
Orthorhombic
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Space Group:
Pbam
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 V:
168.03 ų (Calculated from Unit Cell)
Z:
1
Morphology:
Crystals prismatic to acicular.
Comment:
On synthetic material. Structure is incommensurately modulated.
Crystal Structure
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0001059 | Mullite | Angel R J, Prewitt C T (1986) Crystal structure of mullite: A re-examination of the average structure American Mineralogist 71 1476-1482 |  | 1986 | 0 | 293 | |
| 0001351 | Mullite | Angel R J, McMullan R K, Prewitt C T (1991) Substructure and superstructure of mullite by neutron diffraction Model 1 Neutron American Mineralogist 76 332-342 | | 1991 | 0 | 293 | |
| 0001352 | Mullite | Angel R J, McMullan R K, Prewitt C T (1991) Substructure and superstructure of mullite by neutron diffraction Model 2 X-ray American Mineralogist 76 332-342 | | 1991 | 0 | 293 | |
| 0001618 | Mullite | Balzar D, Ledbetter H (1993) Crystal structure and compressibility of 3:2 mullite American Mineralogist 78 1192-1196 | | 1993 | 0 | 293 | |
| 0001673 | Mullite | Fischer R X, Schneider H, Schmucker M (1994) Crystal structure of Al-rich mullite American Mineralogist 79 983-990 | | 1994 | 0 | 293 | |
| 0002492 | Mullite | Fischer R X, Schneider H (2000) Crystal structure of Cr-mullite American Mineralogist 85 1175-1179 | | 2000 | 0 | 293 | |
| 0002749 | Mullite | Fischer R X, Schmucker M, Angerer P, Schneider H (2001) Crystal structures of Na and K aluminate mullites American Mineralogist 86 1513-1518 | | 2001 | 0 | 293 | |
| 0002750 | Mullite | Fischer R X, Schmucker M, Angerer P, Schneider H (2001) Crystal structures of Na and K aluminate mullites American Mineralogist 86 1513-1518 | | 2001 | 0 | 293 | |
| 0004280 | Mullite | Popovic J, Tkalcec E, Grzeta B, Kurajica S, Schmauch J (2007) Cobalt incorporation in mullite American Mineralogist 92 408-411 | | 2007 | 0 | 293 | |
| 0004281 | Mullite | Popovic J, Tkalcec E, Grzeta B, Kurajica S, Schmauch J (2007) Cobalt incorporation in mullite American Mineralogist 92 408-411 | | 2007 | 0 | 293 | |
| 0006888 | Mullite | Voll D, Lengauer C, Beran A, Schneider H (2001) Infrared band assignment and structural refinement of Al-Si, Al-Ge, and Ga-Ge mullites European Journal of Mineralogy 13 591-604 | 2001 | 0 | 293 | ||
| 0006889 | Mullite | Voll D, Lengauer C, Beran A, Schneider H (2001) Infrared band assignment and structural refinement of Al-Si, Al-Ge, and Ga-Ge mullites European Journal of Mineralogy 13 591-604 | 2001 | 0 | 293 | ||
| 0006890 | Mullite | Voll D, Lengauer C, Beran A, Schneider H (2001) Infrared band assignment and structural refinement of Al-Si, Al-Ge, and Ga-Ge mullites European Journal of Mineralogy 13 591-604 | 2001 | 0 | 293 | ||
| 0006891 | Mullite | Voll D, Lengauer C, Beran A, Schneider H (2001) Infrared band assignment and structural refinement of Al-Si, Al-Ge, and Ga-Ge mullites European Journal of Mineralogy 13 591-604 | 2001 | 0 | 293 | ||
| 0011005 | Mullite | Saalfeld H, Gerlach H (1991) Solid solution and optical properties of (Al,Ge)-mullites Zeitschrift fur Kristallographie 195 65-73 | | 1991 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.39 Å | (50) |
| 3.390 Å | (100) |
| 3.428 Å | (95) |
| 2.694 Å | (40) |
| 2.542 Å | (50) |
| 2.206 Å | (60) |
| 1.5242 Å | (35) |
Comments:
For synthetic material.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 26 : Hadean detrital minerals | |
| Stage 5: Initiation of plate tectonics | <3.5-2.5 |
| 40 : Regional metamorphism (greenschist, amphibolite, granulite facies) | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 50 : Coal and/or oil shale minerals | <0.36 |
| 51 : Pyrometamorphic minerals (see also #54 and #56) | <0.36 |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 54 : Coal and other mine fire minerals (see also #51 and #56) |
Type Occurrence of Mullite
General Appearance of Type Material:
Minute sharp crystals embedded in glass.
Geological Setting of Type Material:
Sillimanite buchites or fused argillaceous sediments occurring as inclusions in Tertiary intrusives.
Associated Minerals at Type Locality:
Reference:
Bowen, N.L., Greig, J.W., Zies, E.G. (1924) Mullite, a silicate of alumina. Journal of the Washington Academy of Sciences: 14: 183-191.
Synonyms of Mullite
Other Language Names for Mullite
Common Associates
Associated Minerals Based on Photo Data:
| 35 photos of Mullite associated with Hematite | Fe2O3 |
| 31 photos of Mullite associated with Pseudobrookite | Fe2TiO5 |
| 22 photos of Mullite associated with Sanidine | K(AlSi3O8) |
| 14 photos of Mullite associated with Tridymite | SiO2 |
| 14 photos of Mullite associated with Osumilite-(Mg) | K◻2Mg2Al3[Al2Si10O30] |
| 13 photos of Mullite associated with Cordierite | (Mg,Fe)2Al3(AlSi5O18) |
| 9 photos of Mullite associated with Phlogopite | KMg3(AlSi3O10)(OH)2 |
| 9 photos of Mullite associated with Topaz | Al2(SiO4)(F,OH)2 |
| 6 photos of Mullite associated with Osumilite | K◻2Fe2+2Al3[Al2Si10O30] |
| 5 photos of Mullite associated with Sapphire | Al2O3 |
Related Minerals - Strunz-mindat Grouping
| 9.AF. | Chegemite | Ca7(SiO4)3(OH)2 |
| 9.AF. | Barwoodite | Mn2+6Nb5+(SiO4)2O3(OH)3 |
| 9.AF. | Jingwenite-(Y) | YAlV4+(SiO4)O2(OH)2 |
| 9.AF.05 | Sillimanite | Al2(SiO4)O |
| 9.AF.05 | Xenolite | Al10Si8O31 |
| 9.AF.10 | Andalusite | Al2(SiO4)O |
| 9.AF.10 | Kanonaite | Mn3+Al(SiO4)O |
| 9.AF.15 | Kyanite | Al2(SiO4)O |
| 9.AF.20 | Krieselite | Al2(GeO4)F2 |
| 9.AF.23 | Boromullite | Al9BSi2O19 |
| 9.AF.25 | Yoderite | Mg(Al,Fe3+)3(SiO4)2O(OH) |
| 9.AF.30 | Magnesiostaurolite | Mg(Mg,Li)3(Al,Mg)18Si8O44(OH)4 |
| 9.AF.30 | Staurolite | Fe2+2Al9Si4O23(OH) |
| 9.AF.30 | Zincostaurolite | Zn2Al9Si4O23(OH) |
| 9.AF.35 | Topaz | Al2(SiO4)(F,OH)2 |
| 9.AF.40 | Norbergite | Mg3(SiO4)F2 |
| 9.AF.45 | Alleghanyite | Mn2+5(SiO4)2(OH)2 |
| 9.AF.45 | Chondrodite | Mg5(SiO4)2F2 |
| 9.AF.45 | Reinhardbraunsite | Ca5(SiO4)2(OH,F)2 |
| 9.AF.45 | Kumtyubeite | Ca5(SiO4)2F2 |
| 9.AF.45 | Hydroxylchondrodite | Mg5(SiO4)2(OH)2 |
| 9.AF.50 | Humite | Mg7(SiO4)3F2 |
| 9.AF.50 | Manganhumite | (Mn2+,Mg)7(SiO4)3(OH)2 |
| 9.AF.50 | Unnamed (Ca-analogue of Humite) | Ca7(SiO4)4F2 |
| 9.AF.50 | Fluorchegemite | Ca7(SiO4)3F2 |
| 9.AF.50 | Unnamed (OH-analogue of humite) | Mg7(SiO4)3(OH)2 |
| 9.AF.55 | Clinohumite | Mg9(SiO4)4F2 |
| 9.AF.55 | Sonolite | Mn2+9(SiO4)4(OH)2 |
| 9.AF.55 | Hydroxylclinohumite | Mg9(SiO4)4(OH)2 |
| 9.AF.60 | Leucophoenicite | Mn2+7(SiO4)3(OH)2 |
| 9.AF.65 | Ribbeite | Mn2+5(SiO4)2(OH)2 |
| 9.AF.70 | Jerrygibbsite | Mn2+9(SiO4)4(OH)2 |
| 9.AF.75 | Franciscanite | Mn2+6(V5+,◻)2(SiO4)2(O,OH)6 |
| 9.AF.75 | Örebroite | Mn2+3(Sb5+,Fe3+)(SiO4)(O,OH)3 |
| 9.AF.75 | Welinite | Mn2+6(W6+,Mg)2(SiO4)2(O,OH)6 |
| 9.AF.75 | Scorticoite | Mn6(Sb,◻)Σ2(SiO4)2O3(OH)3 |
| 9.AF.80 | Ellenbergerite | Mg6(Mg,Ti,Zr,◻)2(Al,Mg)6Si8O28(OH)10 |
| 9.AF.85 | Chloritoid | (Fe2+,Mg,Mn2+)Al2(SiO4)O(OH)2 |
| 9.AF.85 | Magnesiochloritoid | MgAl2(SiO4)O(OH)2 |
| 9.AF.85 | Ottrélite | (Mn2+,Fe2+,Mg)Al2(SiO4)O(OH)2 |
| 9.AF.90 | Poldervaartite | CaCa[SiO3(OH)](OH) |
| 9.AF.90 | Olmiite | CaMn2+[SiO3(OH)](OH) |
| 9.AF.95 | Pilawite-(Y) | Ca2Y2Al4(SiO4)4O2(OH)2 |
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Mullite in petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Mullite
mindat.org URL:
https://www.mindat.org/min-2806.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Mullite
Reference List:
Lenz, Stephan, Birkenstock, Johannes, Fischer, Lennart A., Schneider, Hartmut, Fischer, Reinhard X. (2020) Mullite-2c - a natural polytype of mullite. European Journal of Mineralogy, 32 (2) 235-249 doi:10.5194/ejm-32-235-2020
Localities for Mullite
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
Australia | |
| Loughnan et al. (1960) |
| Spry et al. (1964) |
| R Bottrill in prep |
Austria | |
| U. Kolitsch et al. (2009) +1 other reference |
| Postl et al. (1996) |
| Postl et al. (1996) +1 other reference |
Belgium | |
| Ottenburgs et al. (1998) |
China | |
| Gansu Province Metallurgical and Geological Exploration Team No. 4 (1978) |
| Guangce Zeng et al. (1993) | |
| Querol +9 other references |
Czech Republic | |
| Zacek et al. (1995) |
| David Parfitt collection +2 other references |
| Jirásek (2001) |
| Dalibor Matýsek |
| Ferry FEDIUK |
Egypt | |
| Gian Paolo Sighinolfi et al. (2014) |
France | |
| Barrier D et al. (2004) |
Germany | |
| Pöllmann et al. (2007) |
| Weiß (1990) |
| Weiß (1990) |
| Müller (1967) |
| Schnorrer et al. (2001) |
| in: Stracher +1 other reference |
| Hentschel (1983) |
| Personally collected by Günter Frenz |
| Lapis 1988 (7+8) | |
| Hentschel (1983) |
| Blass +1 other reference |
| Blass +1 other reference | |
| Blass +1 other reference |
| Blass +1 other reference |
| Leu (2017) | |
| Hentschel (1983) |
| Hentschel (1983) | |
| Neschen (n.d.) |
| www.mindat.org (n.d.) +7 other references |
| Hentschel |
| Leu |
| Marko Burkhardt Collection |
| Schäfer |
| Guth et al. (Löley) | |
| Blaß et al. (2012) |
| Schüller |
| Färber (n.d.) |
| T. Witzke (1996) |
| T. Witzke & F. Rüger: Lapis 1998 (7/8) |
Hungary | |
| Szakáll & Gatter: Hun. Min. Spec. |
India | |
| Nayak et al. (2024) |
| Mallick et al. (2005, March) |
Italy | |
| Russo et al. (2011) |
| Burli et al. (2010) |
| Bortolozi (1986) |
| Bortolozi G. (1986) | |
| Renzulli +4 other references |
Japan | |
| Matsubara et al (1998) |
Kenya | |
| Ulianov et al. (2005) |
Mongolia | |
| Savina et al. (2023) |
Netherlands | |
| De Wit et al. (2003) |
New Zealand | |
| Martin Stolworthy Collection |
| Bishop (1965) |
| Personal collection of Rod Martin |
| Collection of Rod Martin |
| Collection of RJ Martin +1 other reference | |
| Thornton (Ed.) | |
| Collection of RJ Martin correlated to ... | |
| Essence of Microscope | |
Poland | |
| Ł. Kruszewski PXRD & EPMA data |
| Ciesielczukk |
| Ł.K. visual/comparative identification ... |
| Ł. Kruszewski visual inspection & ... |
| Ł. Kruszewski visual inspection & ... | |
| Ł. Kruszewski EPMA/PXRD data +1 other reference |
| Cabała +4 other references |
| Pierwoła |
| Lukasz Kruszewski 2005: Minerals arising in cause of underground fires of "Skalny" coal mine dump in Laziska (unpublished) |
| Łukasz Kruszewski preliminary ... |
| Ciesielczuk et al. (2014) | |
| Ł. Kruszewski PXRD and EPMA data |
| Łukasz Kruszewski visual/comparative ... |
Russia | |
| Cesnokov et al. (1998) |
| Bortnikova et al. (2017) |
| Kokh et al. (2023) |
| Sokol et al. (2019) |
| Masaitis (1998) |
Slovakia | |
| Bacsó |
| [European Journal of Mineralogy ... |
| Bolanz et al. (2012) |
South Africa | |
| Mathias et al. (1970) |
South Korea | |
| Choi et al. (2024) |
Spain | |
| Robert A. Jenkins |
| Calvo (2008) |
| Calvo (2008) |
| Abad +3 other references |
Syria | |
| Moore et al. (2020) |
Tajikistan | |
| Sharygin et al. (2009) |
| Nasdala et al. (1993) | |
UK | |
| |
| Day (1999) | |
| N L. Bowen +1 other reference |
| Smith (1965) +2 other references | |
USA | |
| Reidel et al. (2023) |
| - (2005) |
| Piatak et al. (2010) |
| - (2005) |
| AmMin 10:152-155 |
| Piatak et al. (2012) |
| Färber (n.d.) |
Quick NavTopAbout MulliteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatOther InformationMullite in petrologyInternet Links References Localities Locality List
Nickenicher Sattel, Nickenich, Pellenz, Mayen-Koblenz, Rhineland-Palatinate, Germany