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Moganite
A valid IMA mineral species
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About Moganite
Formula:
SiO2
Colour:
Grey
Lustre:
Vitreous
Hardness:
6
Specific Gravity:
2.52 - 2.58
Crystal System:
Monoclinic
Member of:
Name:
After the type locality: MogĂĄn, Grand Canary Island, Spain.
Polymorph of:
This SiO2 modification is not uncommon as a minor component of finely crystalline chalcedony (as well as chert or flint), although some samples may contain up to about 50 vol.% of moganite.
It may be identified by careful powder diffraction analysis or Raman and infrared spectroscopy.
Polymorphous (or polytypic?) with UM2000-61-SiO.
It may be identified by careful powder diffraction analysis or Raman and infrared spectroscopy.
Polymorphous (or polytypic?) with UM2000-61-SiO.
Unique Identifiers
Mindat ID:
2739
Long-form identifier:
mindat:1:1:2739:3
Similar Names
IMA Classification of Moganite
Approved
IMA Formula:
SiO2¡nH2O
Approval year:
1999
First published:
1984
Classification of Moganite
4.DA.20
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
A : With small cations: Silica family
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
D : Metal: Oxygen = 1:2 and similar
A : With small cations: Silica family
7.8.9
7 : Oxides and Hydroxides
8 : Oxides of Si
7 : Oxides and Hydroxides
8 : Oxides of Si
Mineral Symbols
As of 2021 there are now IMAâCNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMAâCNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMAâCNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Mog | IMAâCNMNC | Warr, L.N. (2021). IMAâCNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Mog | Whitney & Evans (2010) | Whitney, D.L. and Evans, B.W. (2010) Abbreviations for names of rock-forming minerals. American Mineralogist, 95, 185â187 doi:10.2138/am.2010.3371 |
| Mog | Warr (2020) | Warr, L.N. (2020) Recommended abbreviations for the names of clay minerals and associated phases. Clay Minerals, 55, 261â264 doi:10.1180/clm.2020.30 |
Physical Properties of Moganite
Vitreous
Transparency:
Translucent
Colour:
Grey
Hardness:
6 on Mohs scale
Density:
2.52 - 2.58 g/cm3 (Measured) 2.55 g/cm3 (Calculated)
Optical Data of Moganite
Type:
Biaxial
RI values:
nα = 1.524 nγ = 1.531
Max. Birefringence:
δ = 0.007
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 Âľm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 Âľm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
None to Very Low
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Dispersion:
not discernible
Chemistry of Moganite
Mindat Formula:
SiO2
Elements listed:
Crystallography of Moganite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Cell Parameters:
a = 8.758 Å, b = 4.876 Å, c = 10.715 Å
β = 90.08°
β = 90.08°
Ratio:
a:b:c = 1.796 : 1 : 2.197
Unit Cell V:
457.573 Ă
Âł
Z:
12
Comment:
Space group is I2/a (Miehe & Graetsch, 1992; Heaney & Post, 2001); the unit cell parameters are from the first reference cited; at ~297 oC transforms into Imab-structured (orthorhombic) phase (Heaney & Post, 2001))
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.33 Ă | (100) |
| 3.39 Ă | (50) |
| 4.45 Ă | (13) |
| 1.81 Ă | (13) |
| 1.369 Ă | (11) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3a: Earthâs earliest Hadean crust | >4.50 |
| 9 : Lava/xenolith minerals (hornfels, sanidinite facies) | |
| Stage 4a: Earthâs earliest continental crust | >4.4-3.0 |
| 20 : Acidic volcanic rocks |
Type Occurrence of Moganite
General Appearance of Type Material:
Nodular masses 1-5 cm in diameter. Also as platy masses 1-10 mm in thickness in cooling cracks.
Geological Setting of Type Material:
Rhyolitic ignimbrites.
Associated Minerals at Type Locality:
Synonyms of Moganite
Other Language Names for Moganite
Relationship of Moganite to other Species
Member of:
Other Members of Silica:
| Chibaite | SiO2 ¡ n(CH4, C2H6, C3H8, i-C4H10) (n = 3/17 (max)) | Iso. m3(2/m3) : Fd3 |
| Coesite | SiO2 | Mon. 2/m : B2/b |
| Cristobalite | SiO2 | Tet. 422 : P41212 |
| 'Keatite' | SiO2 | Tet. 422 : P43212 |
| Lechatelierite | SiO2 | Amor. |
| Melanophlogite | 46SiO2 ¡ 6(N2,CO2) ¡ 2(CH4,N2) | Tet. 4/mmm(4/m2/m2/m) |
| 'Opal-AG' | SiO2 ¡ nH2O | |
| 'Opal-AN' | SiO2 ¡ nH2O | |
| 'Opal-C' | SiO2 ¡ nH2O | |
| 'Opal-CT' | SiO2 ¡ nH2O | |
| Quartz | SiO2 | Trig. 32 : P3121 |
| 'Quartz-beta' | SiO2 | Hex. 622 : P6422 |
| Stishovite | SiO2 | Tet. 4/mmm(4/m2/m2/m) : P42/mnm |
| Tridymite | SiO2 | Tric. 1 |
| 'β-Cristobalite' | SiO2 | Iso. m3m(4/m32/m) : Fd3m |
| 'β-Tridymite' | SiO2 |
Common Associates
Associations Based on Photo Data:
| 48 photos of Moganite associated with 'Chalcedony' | SiO2 |
| 19 photos of Moganite associated with Quartz | SiO2 |
| 1 photo of Moganite associated with Goethite | Fe3+O(OH) |
| 1 photo of Moganite associated with 'Ignimbritic tuff' |
Related Minerals - Strunz-mindat Grouping
| 4.DA. | Bosoite | SiO2 ¡ nCxH2x+2 |
| 4.DA. | Chibaite | SiO2 ¡ n(CH4, C2H6, C3H8, i-C4H10) (n = 3/17 (max)) |
| 4.DA. | 'Carbon Dioxide Ice' | CO2 |
| 4.DA.05 | Quartz | SiO2 |
| 4.DA.10 | Tridymite | SiO2 |
| 4.DA.10 | Opal | SiO2 ¡ nH2O |
| 4.DA.15 | Cristobalite | SiO2 |
| 4.DA.25 | Melanophlogite | 46SiO2 ¡ 6(N2,CO2) ¡ 2(CH4,N2) |
| 4.DA.30 | Lechatelierite | SiO2 |
| 4.DA.35 | Coesite | SiO2 |
| 4.DA.35 | Xiexiandeite | SiO2 |
| 4.DA.40 | Stishovite | SiO2 |
| 4.DA.45 | 'Keatite' | SiO2 |
| 4.DA.50 | Seifertite | SiO2 |
| 4.DA.55 | 'Quartz-beta' | SiO2 |
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.
Internet Links for Moganite
mindat.org URL:
https://www.mindat.org/min-2739.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 Moganite
Reference List:
FlĂśrke, O. W.; Jones, J. B.; Schmincke, H.-U. (1976) A new microcrystalline silica from Gran Canaria. Zeitschrift fĂźr Kristallographie, 143 (1-6). 156-165 doi:10.1524/zkri.1976.143.jg.156(as "SiO2-G")
Dunn, Pete J., Fleischer, Michael, Langley, Richard H., Shigley, James E., Zilczer, Janet A. (1985) New mineral names. American Mineralogist, 70 (7-8) 871-881 p.874
HEANEY, P. J., POST, J. E. (1992) The Widespread Distribution of a Novel Silica Polymorph in Microcrystalline Quartz Varieties. Science, 255 (5043). 441-443 doi:10.1126/science.255.5043.441
Miehe, Gerhard, Graetsch, Heribert (1992) Crystal structure of moganite: a new structure type for silica. European Journal of Mineralogy, 4 (4) 693-706 doi:10.1127/ejm/4/4/0693
Kingma, Kathleen J., Hemley, Russell J. (1994) Raman spectroscopic study of microcrystalline silica. American Mineralogist, 79 (3-4) 269-273
Jambor, John L., Grew, Edward S., Roberts, Andrew C. (1996) New mineral names. American Mineralogist, 81. 1513-1518
GĂśtze, Jens, Nasdala, Lutz, Kleeberg, Reinhard, Wenzel, Marita (1998) Occurrence and distribution of âmoganiteâ in agate/chalcedony: a combined micro-Raman, Rietveld, and cathodoluminescence study. Contributions to Mineralogy and Petrology, 133 (1) 96-105 doi:10.1007/s004100050440
Parthasarathy, Gopalakrishnarao, Kunwar, Ajit Chand, Srinivasan, Ramaswamiah (2001) Occurrence of moganite-rich chalcedony in Deccan flood basalts, Killari, Maharashtra, India. European Journal of Mineralogy, 13 (1). 127-134 doi:10.1127/0935-1221/01/0013-0127
Heaney, Peter J.; Post, Jeffrey E. (2001) Evidence for an I2/a to Imab phase transition in the silica polymorph moganite at ~570 K. American Mineralogist, 86 (11-12). 1358-1366 doi:10.2138/am-2001-11-1204
Rodgers, K. A., Cressey, G. (2001) The occurrence, detection and significance of moganite (SiO2) among some silica sinters. Mineralogical Magazine, 65 (2) 157-167 doi:10.1180/002646101550181
Rodgers, K. A., Hampton, W. A. (2003) Laser Raman identification of silica phases comprising microtextural components of sinters. Mineralogical Magazine, 67 (1) 1-13 doi:10.1180/0026461036710079
Moxon, Terry, RĂ os, Susana (2004) Moganite and water content as a function of age in agate: an XRD and thermogravimetric study. European Journal of Mineralogy, 16 (2) 269-278 doi:10.1127/0935-1221/2004/0016-0269
Heaney, P. J.; McKeown, D. A.; Post, J. E. (2007) Anomalous behavior at the I2/a to Imab phase transition in SiO2-moganite: An analysis using hard-mode Raman spectroscopy. American Mineralogist, 92 (4). 631-639 doi:10.2138/am.2007.2184
Schmidt, Patrick, Bellot-Gurlet, Ludovic, Slodczyk, Aneta, FrĂśhlich, François (2012) A hitherto unrecognised band in the Raman spectra of silica rocks: influence of hydroxylated SiâO bonds (silanole) on the Raman moganite band in chalcedony and flint (SiO2) Physics and Chemistry of Minerals, 39 (6) 455-464 doi:10.1007/s00269-012-0499-7
Zhang, M., Moxon, T. (2014) Infrared absorption spectroscopy of SiO2-moganite. American Mineralogist, 99 (4) 671-680 doi:10.2138/am.2014.4589
Localities for Moganite
Showing 88 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
â - 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.
Antarctica | |
| Sorrell (n.d.) |
Australia | |
| Fetherston et al. (2013) |
Austria | |
| Mineralienatlas.de +1 other reference |
| GĂśtzinger | |
Brazil | |
| Vanrusselt (2023) |
| Personal knowledge from years of ... |
Bulgaria | |
| Janakieva +3 other references | |
| Janakieva +3 other references | |
| Janakieva +3 other references |
Canada | |
| Grand Manan Museum |
China | |
| Zhou et al. (2022) |
| Zhang +2 other references |
| Song et al. (2025) |
Czech Republic | |
| Matýsek et al. (2025) |
| KonĂÄkovĂĄ et al. (2021) | |
| Matýsek et al. (2025) |
| Matýsek et al. (2025) |
| Matýsek et al. (2025) |
| Matýsek et al. (2025) |
| Matýsek et al. (2025) |
| Matýsek et al. (2025) |
| Matýsek et al. (2025) |
| Matýsek et al. (2025) |
| Matýsek et al. (2025) |
| KonĂÄkovĂĄ Ĺ . et al. (2016) |
Egypt | |
| Hassan (2014) |
Finland | |
| Valkama (2019) |
| Jouni Laurinperä photo and collection ( photo id 965669 + 965670 ) | |
France | |
| G. Demarcq |
| |
| F. Roulin et al. |
Germany | |
| https://www.mineralienatlas.de/?l=53526 |
| Petitjean et al. (2007) |
| www.mineralienatlas.de (2025) |
| Witzke et al. (2001) |
Greece | |
| Bourli et al. (2021) |
| Bourli et al. (2021) | |
| Bourli et al. (2021) | |
| Bourli et al. (2021) |
Hungary | |
| |
| GEODA |
India | |
| Eur. Jour. Min. 13 (2001) |
Indonesia | |
| www.mindat.org (n.d.) |
Italy | |
| Napoleoni et al. (2021) +1 other reference |
Japan | |
| Confirmed by Dr D. Nishio-Hamane using ... |
| Matsubara and Miyawaki (2006) |
Luxembourg | |
| www.mnhn.lu (n.d.) +1 other reference |
Mongolia | |
| https://geo.web.ru/druza/l-Arz-Bogdo.htm |
Myanmar | |
| Aung et al. (2021) |
Netherlands | |
| T.G. Nijland | |
New Zealand | |
| Mineralogical Magazine +4 other references |
Norway | |
| Kvamsdal (1999) |
Poland | |
| Ĺ. Kruszewski EPMA/PXRD data +1 other reference |
| Ĺ. Kruszewski (PXRD data) |
Portugal | |
| Oliveira et al. (2025) |
Romania | |
| UdubaÂŞa et al. (2006) |
| minerals-of-the-carpathians.eu (2008) |
| HĂŽrtopanu (1997) +1 other reference |
| UdubaÂŞa et al. (2006) |
Russia | |
| Svetova et al. (2023) |
| Sidorov A.A. Mineralogy of Vodinskoe ... |
Slovakia | |
| ÄuÄa (1993) |
| Matýsek et al. (2025) | |
| Matýsek et al. (2025) |
| KodÄra et al. (1986) |
| KodÄra et al. (1986) | |
| KodÄra et al. (1986) |
| KodÄra et al. (1986) | |
| Matýsek et al. (2025) |
| KodÄra et al. (1986) |
Spain (TL) | |
| Dunn et al. (1985) |
| Calvo Rebollar (2016) +1 other reference | |
| American Mineralogist (1993) |
| Herrero +4 other references | |
Switzerland | |
| Ansermet et al. (2024) |
UK | |
| Ford et al. (1993) |
| Render (n.d.) |
| ... |
Ukraine | |
| Klimchouk (2012) |
USA | |
| Natkaniec-Nowak et al. (2020) |
| www.mindat.org (n.d.) |
| Eckel et al. (1997) |
| Rocks & Minerals (July-August, 2002) |
| Eckel et al. (1997) | |
| Volkert et al. (2023) |
| Volkert et al. (2023) |
| Ward's Natural Science Establishment (Rochester, NY) |
Quick NavTopAbout MoganiteUnique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Kodono, Kamiukena District, Ehime Prefecture, Japan