Åkermanite
A valid IMA mineral species - grandfathered
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About Åkermanite
Anders Richard Åkerman (1837-1922)
Formula:
Ca2Mg[Si2O7]
Colour:
Colorless, yellowish gray, green, brown
Lustre:
Vitreous, Resinous
Hardness:
5 - 6
Specific Gravity:
2.944
Crystal System:
Tetragonal
Member of:
Name:
First described from samples of slags from furnace iron production found at 3 furnace localities: Hofors, Löfsjöen and Mölnbo, Sweden (Vogt 1884). Named by the Norwegian geologist, professor Johan Herman Lie Vogt (1858-1932) in honor of Anders Richard Åkerman (1837-1922), Swedish metallurgist. During his comprehensive study of the mineralogy of slag products, Vogt discovered a new Ca-Mg-silicate, and named the mineral Åkermanit. Åkerman had kindly given J.H.L.Vogt access to Stockholms Bergskolas large collection of slags. It was in samples from this collection Vogt discovered the mineral.
Unique Identifiers
IMA Classification of Åkermanite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Ca2MgSi2O7
Classification of Åkermanite
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
55.4.1.1
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
14.6.9
14 : Silicates not Containing Aluminum
6 : Silicates of Ca with alkali or Mg or both
14 : Silicates not Containing Aluminum
6 : Silicates of Ca with alkali or Mg or both
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 |
|---|---|---|
| Åk | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Ak | Kretz (1983) | Kretz, R. (1983) Symbols of rock-forming minerals. American Mineralogist, 68, 277–279. |
| Ak | 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 |
| Ak | 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 |
| Ak | 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 Åkermanite
Vitreous, Resinous
Transparency:
Transparent, Translucent
Colour:
Colorless, yellowish gray, green, brown
Comment:
In thin section, colorless to yellow.
Streak:
White
Hardness:
5 - 6 on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
Distinct on {001} , poor on {110}
Distinct on {001} , poor on {110}
Fracture:
Irregular/Uneven, Conchoidal
Density:
2.944 g/cm3 (Measured) 2.922 g/cm3 (Calculated)
Optical Data of Åkermanite
Type:
Uniaxial (+)
RI values:
nω = 1.632 nε = 1.640
Max Birefringence:
δ = 0.008
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
Chemistry of Åkermanite
Mindat Formula:
Ca2Mg[Si2O7]
Elements listed:
Crystallography of Åkermanite
Crystal System:
Tetragonal
Class (H-M):
4 2m - Scalenohedral
Space Group:
P4 21m
Cell Parameters:
a = 7.8288(8) Å, c = 5.0052(2) Å
Ratio:
a:c = 1 : 0.639
Unit Cell V:
306.77 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Crystals short prismatic to thin tabular, which may resemble squashed, octahedrally-modified cubes; granular, massive.
Twinning:
On {100} and 001 , cruciform.
Comment:
Synthetic material
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.87 Å | (100) |
| 3.09 Å | (30) |
| 1.764 Å | (30) |
| 2.039 Å | (20) |
| 2.488 Å | (18) |
| 3.73 Å | (14) |
| 5.55 Å | (12) |
Comments:
Synthetic.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 1: Primary nebular phases | 4.567-4.561 |
| 3 : Solar nebular condensates (CAIs, AOAs, URIs) | >4.565 |
| Stage 2: Planetesimal differentiation and alteration | 4.566-4.550 |
| 6 : Secondary asteroid phases | 4.566-4.560 |
| Stage 3a: Earth’s earliest Hadean crust | >4.50 |
| 8 : Mafic igneous rocks | |
| High-𝑇 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 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 51 : Pyrometamorphic minerals (see also #54 and #56) | <0.36 |
Geological Setting:
A product of contact metamorphism of siliceous limestones and dolostones, and in rocks of the sanidinite facies. Also forms from alkalic magmas rich in calcium.
Synonyms of Åkermanite
Other Language Names for Åkermanite
German:Åkermanit
Oakermanit
Okermanit
Oakermanit
Okermanit
Norwegian:Åkermanitt
Russian:Окерманит
Simplified Chinese:镁黄长石
Spanish:Åkermanita
Oakermanita
Okermanita
Oakermanita
Okermanita
Varieties of Åkermanite
| Justite (of Hofmann-Degen) | An artificial (anthropogenic) mineral found as crystals in lead furnaces in Clausthal, Harz, Germany. A ferroan zincian Åkermanite. |
Relationship of Åkermanite to other Species
Member of:
Other Members of this group:
| Alumoåkermanite | (CaNa)Al[Si2O7] | Tet. 4 2m : P4 21m |
| Bennesherite | Ba2Fe2+[Si2O7] | Tet. 4 2m : P4 21m |
| Ferri-gehlenite | Ca2Fe3+[AlSiO7] | |
| Gehlenite | Ca2Al[AlSiO7] | Tet. 4 2m : P4 21m |
| Gugiaite | Ca2Be[Si2O7] | Tet. 4 2m : P4 2m |
| Hardystonite | Ca2Zn[Si2O7] | Tet. 4 2m : P4 21m |
| Hydroxylgugiaite | (Ca,◻)2(Si,Be)[(Be,Si)2O5.5(OH)1.5] | Tet. 4 2m : P4 21m |
| Okayamalite | Ca2B[BSiO7] | Tet. 4 2m : P4 21m |
Forms a series with:
Common Associates
Associated Minerals Based on Photo Data:
| 9 photos of Åkermanite associated with Kalsilite | KAlSiO4 |
| 3 photos of Åkermanite associated with Fluorapatite | Ca5(PO4)3F |
| 2 photos of Åkermanite associated with Saponite | Ca0.25(Mg,Fe)3((Si,Al)4O10)(OH)2 · nH2O |
| 1 photo of Åkermanite associated with Hardystonite | Ca2Zn[Si2O7] |
| 1 photo of Åkermanite associated with Ettringite Group | |
| 1 photo of Åkermanite associated with Kottenheimite | Ca 3Si(SO4)2(OH)6 · 12H2O |
| 1 photo of Åkermanite associated with Nepheline | Na3K(Al4Si4O16) |
| 1 photo of Åkermanite associated with Ettringite | Ca6Al2(SO4)3(OH)12 · 26H2O |
| 1 photo of Åkermanite associated with Cuprite | Cu2O |
| 1 photo of Åkermanite associated with Linarite | PbCu(SO4)(OH)2 |
Related Minerals - Strunz-mindat Grouping
| 9.BB.10 | Cebollite | Ca5Al2(SiO4)3(OH)4 |
| 9.BB.10 | Gehlenite | Ca2Al[AlSiO7] |
| 9.BB.10 | Gugiaite | Ca2Be[Si2O7] |
| 9.BB.10 | Hardystonite | Ca2Zn[Si2O7] |
| 9.BB.10 | Jeffreyite | (Ca,Na)2(Be,Al)(Si2O7,HSi2O7) |
| 9.BB.10 | Okayamalite | Ca2B[BSiO7] |
| 9.BB.10 | Ferri-gehlenite | Ca2Fe3+[AlSiO7] |
| 9.BB.10 | Alumoåkermanite | (CaNa)Al[Si2O7] |
| 9.BB.10 | Hydroxylgugiaite | (Ca,◻)2(Si,Be)[(Be,Si)2O5.5(OH)1.5] |
| 9.BB.15 | Barylite | Be2Ba(Si2O7) |
| 9.BB.15 | Barylite-1O | Be2Ba(Si2O7) |
| 9.BB.20 | Andrémeyerite | BaFe2+2(Si2O7) |
| 9.BB.20 | Bennesherite | Ba2Fe2+[Si2O7] |
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.
Åkermanite in petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Åkermanite
mindat.org URL:
https://www.mindat.org/min-70.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 Åkermanite
Reference List:
Localities for Åkermanite
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.
Atlantic Ocean | |
| Gablina et al. (2018) |
| Gablina et al. (2018) | |
Austria | |
| Kolitsch (2013) |
Canada | |
| OWENS et al. (2010) |
| Am Min 85:1595–1605 (2000) | |
| Sabina (1968) |
| Mineralogical Society of America - ... | |
| Sabina (1968) |
China | |
| Xiyue Wang et al. (1987) |
Czech Republic | |
| Pauliš P. Mineralogické lokality ... |
| Žáček V. |
DR Congo | |
| Andersen et al. (2014) |
France | |
| publication date: November 2018 +1 other reference |
Germany | |
| Keller et al. (1995) |
| Neschen (n.d.) |
| |
| Bender et al. (1994) +1 other reference |
| Blaß et al. (1995) |
| Luetcke (n.d.) +1 other reference | |
| Neschen (n.d.) |
| Christof Schäfer |
| in the collection of Christof Schäfer | |
| Skrzyńska et al. (2023) | |
| Blaß et al. (1999) |
| in the collection of Christof Schäfer | |
| Aksenov et al. (2014) |
| in the collection of Christof Schäfer +1 other reference |
Iraq | |
| |
Italy | |
| [Lapis 1994:5 p.13-23 |
| |
| Vanrusselt (2023) |
| Stoppa F. |
| Joel Dyer collection |
Japan | |
| The Mineral Species of Japan (5th ed) |
Middle East | |
| Gross (1977) | |
Morocco | |
| Berger et al. (2009) | |
Namibia | |
| Ettler et al. (2009) |
Norway | |
| Jamtveit et al. (1997) |
Romania | |
| Szakáll |
| Szakáll et al. (2010) | |
Russia | |
| Sklyarov et al. (2021) |
| Sokol et al. (2019) +1 other reference |
| Pavel.M. Kartashov (n.d.) |
| ... |
| Arzamastsev et al. (1990) +2 other references | |
| Kalinkina et al. (2001) |
Slovakia | |
| [[1]]Reato |
| Martin Števko-unpublished |
South Africa | |
| Cairncross et al. (1995) |
| Von Bezing (1991) |
Sweden | |
| Sandström et al. (2010) |
UK | |
| S. Rust collection |
| P. A. Sabine (1985) |
| Tilley et al. (1931) | |
| Tindle (2008) | |
| Agrell (1965) +2 other references |
USA | |
| Mineralogical Society of America - ... |
| Eckel et al. (1997) |
| Mineralogical Society of America - ... |
| Mineralogical Society of America - ... |
| EOS: 60: 423. +1 other reference |
| Rocks & Minerals: 66 (3) |
Outer Space | |
| Posch et al. (2007) |
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Graulay quarry, Hillesheim, Gerolstein, Vulkaneifel, Rhineland-Palatinate, Germany