Alumoåkermanite
A valid IMA mineral species
This page is currently not sponsored. Click here to sponsor this page.
About Alumoåkermanite
Formula:
(CaNa)Al[Si2O7]
The mindat formula represents the simplified end-member composition. This composition was historically known as "soda melilite".
Colour:
Light brown
Lustre:
Vitreous
Hardness:
4½ - 5
Specific Gravity:
2.96
Crystal System:
Tetragonal
Member of:
Name:
For the mineral åkermanite and its aluminum content.
This page provides mineralogical data about Alumoåkermanite.
Name Encoding
ASCII-7:
Alumoakermanite
Unique Identifiers
Mindat ID:
39212
Long-form identifier:
mindat:1:1:39212:9
IMA Classification of Alumoåkermanite
Classification of Alumoåkermanite
9.BB.10
9 : SILICATES (Germanates)
B : Sorosilicates
B : Si2O7 groups, without non-tetrahedral anions; cations in tetrahedral [4] and greater coordination
9 : SILICATES (Germanates)
B : Sorosilicates
B : Si2O7 groups, without non-tetrahedral anions; cations in tetrahedral [4] and greater coordination
55.4.1.5
55 : SOROSILICATES Si2O7 Groups,Generally with no Additional Anions
4 : Si2O7 Groups, Generally with No Additional Anions with cations in [8] and lower coordination
55 : SOROSILICATES Si2O7 Groups,Generally with no Additional Anions
4 : Si2O7 Groups, Generally with No Additional Anions with cations in [8] and lower coordination
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Aåk | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Alumoåkermanite
Vitreous
Transparency:
Translucent
Colour:
Light brown
Streak:
White
Hardness:
4½ - 5 on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Parting:
none
Fracture:
Irregular/Uneven
Density:
2.96(2) g/cm3 (Measured) 3.00 g/cm3 (Calculated)
Optical Data of Alumoåkermanite
Type:
Uniaxial (-)
RI values:
nω = 1.635(1) nε = 1.625(2)
Max. Birefringence:
δ = 0.010
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 µm 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 µm 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:
High (positive)
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
Interference Figure:
This shows the idealized uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Optical Extinction:
straight
Pleochroism:
Non-pleochroic
Chemistry of Alumoåkermanite
Mindat Formula:
(CaNa)Al[Si2O7]
The mindat formula represents the simplified end-member composition. This composition was historically known as "soda melilite".
The mindat formula represents the simplified end-member composition. This composition was historically known as "soda melilite".
Element Weights:
Crystallography of Alumoåkermanite
Crystal System:
Tetragonal
Class (H-M):
42m - Scalenohedral
Space Group:
P421m
Cell Parameters:
a = 7.766(4) Å, c = 5.0297(4) Å
Ratio:
a:c = 1 : 0.648
Unit Cell V:
303.35 ų (Calculated from Unit Cell)
Z:
2
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.712 Å | (13) |
| 3.075 Å | (25) |
| 2.859 Å | (100) |
| 2.456 Å | (32) |
| 1.830 Å | (12) |
| 1.757 Å | (19) |
| 1.736 Å | (13) |
| 1.386 Å | (13) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3a: Earth’s earliest Hadean crust | >4.50 |
| 8 : Mafic igneous rocks | |
| High-? alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks | |
| 36 : Carbonatites, kimberlites, and related igneous rocks | |
| Stage 5: Initiation of plate tectonics | <3.5-2.5 |
| 40 : Regional metamorphism (greenschist, amphibolite, granulite facies) | |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 56 : Slag and smelter minerals (see also #51 and #55) |
Type Occurrence of Alumoåkermanite
General Appearance of Type Material:
Tabular phenocrysts (up to 1.5 mm) and microphenocrysts in a fine-grained groundmass.
Place of Conservation of Type Material:
Mineralogical Museum, Department of Mineralogy, St. Petersburg State University, St. Petersburg, Russia, sample OL 218, catalogue number 1/19407.
Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, Russia, sample OL 244, catalogue number 3823/1.
Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, Russia, sample OL 244, catalogue number 3823/1.
Geological Setting of Type Material:
Olivine-free melilite-nephelinitic ashes and lapilli-tuff.
Associated Minerals at Type Locality:
Synonyms of Alumoåkermanite
Other Language Names for Alumoåkermanite
Relationship of Alumoåkermanite to other Species
Member of:
Other Members of Melilite Group:
| Åkermanite | Ca2Mg[Si2O7] | Tet. 42m : P421m |
| Bennesherite | Ba2Fe2+[Si2O7] | Tet. 42m : P421m |
| 'Ferri-gehlenite' | Ca2Fe3+[AlSiO7] | |
| Ferroåkermanite | Ca2Fe[Si2O7] | Tet. 42m : P421m |
| Gehlenite | Ca2Al[AlSiO7] | Tet. 42m : P421m |
| Gugiaite | Ca2Be[Si2O7] | Tet. 42m : P42m |
| Hardystonite | Ca2Zn[Si2O7] | Tet. 42m : P421m |
| Hydroxylgugiaite | (Ca,◻)2(Si,Be)[(Be,Si)2O5.5(OH)1.5] | Tet. 42m : P421m |
| Okayamalite | Ca2B[BSiO7] | Tet. 42m : P421m |
Common Associates
Associations Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 9.BB.10 | Hardystonite | Ca2Zn[Si2O7] |
| 9.BB.10 | Okayamalite | Ca2B[BSiO7] |
| 9.BB.10 | Jeffreyite | (Ca,Na)2(Be,Al)(Si2O7,HSi2O7) |
| 9.BB.10 | Åkermanite | Ca2Mg[Si2O7] |
| 9.BB.10 | 'Ferri-gehlenite' | Ca2Fe3+[AlSiO7] |
| 9.BB.10 | Gehlenite | Ca2Al[AlSiO7] |
| 9.BB.10 | Ferroåkermanite | Ca2Fe[Si2O7] |
| 9.BB.10 | Cebollite | Ca5Al2(SiO4)3(OH)4 |
| 9.BB.10 | Hydroxylgugiaite | (Ca,◻)2(Si,Be)[(Be,Si)2O5.5(OH)1.5] |
| 9.BB.10 | Gugiaite | Ca2Be[Si2O7] |
| 9.BB.15 | Barylite | Be2Ba(Si2O7) |
| 9.BB.15 | 'Barylite-1O' | Be2Ba(Si2O7) |
| 9.BB.20 | Bennesherite | Ba2Fe2+[Si2O7] |
| 9.BB.20 | Andrémeyerite | BaFe2+2(Si2O7) |
Fluorescence of Alumoåkermanite
none
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 Alumoåkermanite
mindat.org URL:
https://www.mindat.org/min-39212.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 Alumoåkermanite
Reference List:
Louisnathan, S. John (1970) The crystal structure of synthetic soda melilite, CaNaAlSi2O7. Zeitschrift für Kristallographie, 131 (1-6). 314-321 doi:10.1524/zkri.1970.131.1-6.314
Fitton, J. G., Hughes, D. J. (1981) Strontian melilite in a nephelinite lava from Etinde, Cameroon. Mineralogical Magazine, 44 (335) 261-264 doi:10.1180/minmag.1981.044.335.03
Bindi, Luca, Bonazzi, Paola, Fitton, J. Godfrey (2001) Crystal chemistry of strontian soda melilite from nephelinite lava of Mt. Etinde, Cameroon. European Journal of Mineralogy, 13 (1) 121-125 doi:10.1127/0935-1221/01/0013-0121
Wiedenmann, D., Zaitsev, A. N., Britvin, S. N., Krivovichev, S. V., Keller, J. (2009) Errata: Alumoåkermanite, (Ca,Na)2(AI,Mg,Fe2+)(Si2O7), a new mineral from the active carbonatite-nephelinite-phonolite volcano Oldoinyo Lengai, northern Tanzania. Mineralogical Magazine, 73 (6) 1063 doi:10.1180/s0026461x00053834
Wiedenmann, D., Zaitsev, A. N., Britvin, S. N., Krivovichev, S. V., Keller, J. (2009) Alumoåkermanite, (Ca,Na)2(Al,Mg,Fe2+)(Si2O7), a new mineral from the active carbonatite-nephelinite-phonolite volcano Oldoinyo Lengai, northern Tanzania. Mineralogical Magazine, 73 (3) 373-384 doi:10.1180/minmag.2009.073.3.373
Localities for Alumoåkermanite
Showing 20 localities.
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.
Cameroon | |
| Fitton et al. (1981) |
Czech Republic | |
| Jirasek et al. (2026) |
France | |
| Boisson et al. (2019) |
Germany | |
| in the collection of Christof Schäfer |
| Skrzyńska et al. (2023) | |
| Juroszek et al. (2025) | |
| EMPA data V. V. SHARYGIN (Novosibirsk, Ru) +1 other reference |
| Sharygin (2012) | |
| in the collection of Christof Schäfer +1 other reference | |
| Blaß et al. (2014) |
Israel | |
| Juroszek et al. (2025) |
| Krzątała et al. (2023) | |
| Galuskin et al. (2024) |
Mongolia | |
| Savina et al. (2020) |
Russia | |
| Sharygin et al. (2018) |
| Pavel M. Kartashov (n.d.) |
| Bosio Paolo |
Slovakia | |
| Reato et al. (2022) |
Tanzania (TL) | |
| Wiedenmann et al. (2009) +2 other references |
USA | |
| Färber (n.d.) |
Quick NavTopAbout AlumoåkermaniteName EncodingUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatFluorescence Other InformationInternet Links References Localities Locality List
Lapanouse-de-Sévérac slag locality, Sévérac-d'Aveyron, Rodez, Aveyron, Occitanie, France