Aegirine-augite
A valid IMA mineral species
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About Aegirine-augite
Formula:
(NaaCabFe2+cMgd)(Fe3+eAlfFe2+gMgh)Si2O6
a+b+c+d = 1
e+f+g=h = 1
a = e+f
0.2 ≤ a ≤ 0.8
e > f
The IMA gives the formula as (Ca,Na)(Fe3+,Mg,Fe2+)Si2O6.
e+f+g=h = 1
a = e+f
0.2 ≤ a ≤ 0.8
e > f
The IMA gives the formula as (Ca,Na)(Fe3+,Mg,Fe2+)Si2O6.
Hardness:
6
Crystal System:
Monoclinic
Member of:
Aegirine-augite was mostly treated as a variety until Joan R. Clark and James J. Papike (1968) redefined aegirine-augite from a neotype location, although the validation of aegirine-augite did not materially alter the original description except to restrict the crystal structure. It was formally redefined as part of the IMA's restructuring of the Pyroxene group by Morimoto et al. (1988), see diagram below.
Unique Identifiers
Mindat ID:
32
Long-form identifier:
mindat:1:1:32:7
Classification of Aegirine-augite
Accepted names for Na pyroxenes (after Morimoto et al., 1988).
IMA Classification of Aegirine-augite
Approved
IMA status notes:
Redefined by the IMA
IMA Formula:
(Ca,Na)(Fe3+,Mg,Fe2+)Si2O6
Approval history:
Redefined by IMA: 1988 (special procedure).
9.DA.20
9 : SILICATES (Germanates)
D : Inosilicates
A : Inosilicates with 2-periodic single chains, Si2O6; pyroxene family
9 : SILICATES (Germanates)
D : Inosilicates
A : Inosilicates with 2-periodic single chains, Si2O6; pyroxene family
65.1.3b.2
65 : INOSILICATES Single-Width,Unbranched Chains,(W=1)
1 : Single-Width Unbranched Chains, W=1 with chains P=2
65 : INOSILICATES Single-Width,Unbranched Chains,(W=1)
1 : Single-Width Unbranched Chains, W=1 with chains P=2
16.24.1
16 : Silicates Containing Aluminum and other Metals
24 : Aluminosilicates of Fe, Mg, Ca and alkalis
16 : Silicates Containing Aluminum and other Metals
24 : Aluminosilicates of Fe, Mg, Ca and alkalis
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 for Standard |
|---|---|---|
| Aeg-Aug | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Aeg-Aug | Kretz (1983) | Kretz, R. (1983) Symbols of rock-forming minerals. American Mineralogist, 68, 277–279. |
| Aeg-Aug | 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 |
| Aeg-Aug | 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 |
Physical Properties of Aegirine-augite
Hardness:
6 on Mohs scale
Optical Data of Aegirine-augite
Type:
Biaxial (-)
RI values:
nα = 1.7 - 1.76 nβ = 1.71 - 1.8 nγ = 1.73 - 1.813
2V:
Measured: 70° to 110°, Calculated: 58° to 72°
Max. Birefringence:
δ = 0.030 - 0.053
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:
Very 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 biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
r > v moderate
Chemistry of Aegirine-augite
Mindat Formula:
(NaaCabFe2+cMgd)(Fe3+eAlfFe2+gMgh)Si2O6
a+b+c+d = 1
e+f+g=h = 1
a = e+f
0.2 ≤ a ≤ 0.8
e > f
The IMA gives the formula as (Ca,Na)(Fe3+,Mg,Fe2+)Si2O6.
a+b+c+d = 1
e+f+g=h = 1
a = e+f
0.2 ≤ a ≤ 0.8
e > f
The IMA gives the formula as (Ca,Na)(Fe3+,Mg,Fe2+)Si2O6.
Chemical Analysis
Oxide wt%:
| 1 | 2 | 3 | |
|---|---|---|---|
| SiO2 | 51,10 % | 52.14 % | 52.59 % |
| TiO2 | 0.28 % | 0.47 % | 0.23 % |
| ZrO2 | 1.30 % | 0.06 % | |
| SnO2 | 0.12 % | ||
| Al2O3 | 1.02 % | 0.29 % | 0.13 % |
| Fe2O3 | 15.77 % | ||
| FeO | 9.62 % | ||
| MnO | 1.13 % | 1.36 % | 0.95 % |
| MgO | 0.96 % | 4.92 % | 7.10 % |
| CaO | 9.72 % | 12.14 % | 14.08 % |
| Na2O | 7.66 % | 6.99 % | 5.69 % |
| V2O3 | 0.66 % | 2.00 % | |
| Fe2O3* | 16.39 % | 12.13 % | |
| FeO* | 4.60 % | 5.02 % | |
| ZnO | 0.06 % | 0.03 % | |
| SrO | 0.05 % | 0.05 % | |
| NiO | 0.02 % | ||
| Total: | 98.58 % | 100.13 % | 100.02 % |
Empirical formulas:
| Sample ID | Empirical Formula |
|---|---|
| 2 | (Na0.52Ca0.48)(Fe3+0.47Mg0.28Fe2+0.15Mn2+0.04V0.02Ca0.02Ti0.01)[Si1.99Al0.01O6] |
| 3 | (Ca0.57Na0.42Mn2+0.01)(Mg0.40Fe3+0.35Fe2+0.16V0.06Mn2+0.02Ti0.01)[Si2.00O6] |
Sample references:
| ID | Locality | Reference | Notes |
|---|---|---|---|
| 1 | Skutesundskjær, Barkevik area, Larvik Commune, Vestfold, Norway | Contains 68ppm Li | |
| 2 | North Wilson pit, Union Carbide Mine, Wilson Springs, Garland County, Arkansas, USA | average of 2 analyses of patchy "higher z" zones in abundant aegirine-augite, in wollastonite. Normalized to ∑(cations) = 4. *Fe3+/∑Fe calculated by charge balance. | |
| 3 | " " | average of 2 analyses of the main "lower z" portions of abundant aegirine-augite, in wollastonite. Normalized to ∑(cations) = 4. *Fe3+/∑Fe calculated by charge balance. |
Crystallography of Aegirine-augite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/b
Setting:
C2/c
Cell Parameters:
a = 9.663(3) Å, b = 8.813(3) Å, c = 5.2184(16) Å
β = 106.40(2)°
β = 106.40(2)°
Ratio:
a:b:c = 1.096 : 1 : 0.592
Unit Cell V:
426.32 ų (Calculated from Unit Cell)
Z:
4
Comment:
Cell data from Mills & Groat (2008).
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3a: Earth’s earliest Hadean crust | >4.50 |
| 7 : Ultramafic igneous rocks | |
| Stage 4a: Earth’s earliest continental crust | >4.4-3.0 |
| 19 : Granitic intrusive rocks | |
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) | |
| 26 : Hadean detrital minerals | |
| 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 |
| 39 : High-? metamorphism (blueschist, eclogite, ultrahigh ? facies) | |
| 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 |
Synonyms of Aegirine-augite
Other Language Names for Aegirine-augite
Dutch:Aegirine-augiet
French:Aegirine-augite
Japanese:エジリン普通輝石
Norwegian:Ægirin-augitt
Simplified Chinese:霓辉石
Varieties of Aegirine-augite
| Blanfordite | Mn-bearing variety of aegirine-augite. |
| Grünblende | A variety of Augite/Aegirin-Augite/Aegirine. Acicular crystals of these pyroxenes covering a quartz xenolith. Literally "green blende". Originally reported from the Eifel, Germany. See also Porricin. |
| Porricin | A variety of Augite/Aegirin-Augite/Aegirine. Acicular crystals of these pyroxenes covering a quartz xenolith. Originally reported from the Eifel, Germany. See also Grünblende. |
| Urbanite | An Fe-rich augite or aegirine-augite. |
Relationship of Aegirine-augite to other Species
Member of:
Other Members of Clinopyroxene Subgroup:
| Aegirine | NaFe3+Si2O6 | Mon. 2/m : B2/b |
| Augite | (CaxMgyFez)(Mgy1Fez1)Si2O6 | Mon. 2/m : B2/b |
| Burnettite | CaVAlSiO6 | Mon. 2/m : B2/b |
| Clinoenstatite | MgSiO3 | Mon. 2/m : P21/b |
| Clinoferrosilite | Fe2+2Si2O6 | Mon. 2/m : P21/b |
| Colomeraite | NaTi3+Si2O6 | Mon. 2/m : B2/b |
| Davisite | CaScAlSiO6 | Mon. 2/m : B2/b |
| Diopside | CaMgSi2O6 | Mon. 2/m : B2/b |
| Esseneite | CaFe3+[AlSiO6] | Mon. 2/m : B2/b |
| Grossmanite | CaTi3+ AlSiO6 | Mon. 2/m : B2/b |
| Hedenbergite | CaFe2+Si2O6 | Mon. 2/m : B2/b |
| Jadeite | Na(Al,Fe3+)Si2O6 | Mon. 2/m : B2/b |
| Jervisite | NaSc3+Si2O6 | Mon. 2/m : B2/b |
| Johannsenite | CaMn2+Si2O6 | Mon. 2/m : B2/b |
| Kanoite | Mn2+MgSi2O6 | Mon. 2/m : P21/b |
| Kosmochlor | NaCrSi2O6 | Mon. 2/m : B2/b |
| Kushiroite | CaAlAlSiO6 | Mon. 2/m : B2/b |
| Namansilite | NaMn3+Si2O6 | Mon. 2/m : B2/b |
| Natalyite | NaV3+Si2O6 | Mon. 2/m : B2/b |
| Omphacite | (NaaCabFe2+cMgd)(AleFe3+fFe2+gMgh)Si2O6 | Mon. 2/m |
| Petedunnite | CaZnSi2O6 | Mon. 2/m : B2/b |
| Pigeonite | (CaxMgyFez)(Mgy1Fez1)Si2O6 | Mon. 2/m : P21/b |
| Ryabchikovite | CuMgSi2O6 | Mon. 2/m : P21/b |
| Spodumene | LiAlSi2O6 | Mon. 2/m : B2/b |
| Tissintite | (Ca,◻)AlSi2O6 | Mon. 2/m : B2/b |
| 'UM2003-36-SiO:CaNa' | NaCrSi2O6 - CaMgSi2O6 | Mon. 2/m : B2/b |
Common Associates
Associations Based on Photo Data:
| 34 photos of Aegirine-augite associated with Quartz | SiO2 |
| 20 photos of Aegirine-augite associated with Sanidine | K(AlSi3O8) |
| 15 photos of Aegirine-augite associated with Nepheline | Na3K(Al4Si4O16) |
| 15 photos of Aegirine-augite associated with Nosean | Na8(Al6Si6O24)(SO4) · H2O |
| 11 photos of Aegirine-augite associated with Microcline | K(AlSi3O8) |
| 11 photos of Aegirine-augite associated with Magnetite | Fe2+Fe3+2O4 |
| 10 photos of Aegirine-augite associated with Titanite | CaTiO(SiO4) |
| 10 photos of Aegirine-augite associated with Albite | Na(AlSi3O8) |
| 9 photos of Aegirine-augite associated with Calcite | CaCO3 |
| 9 photos of Aegirine-augite associated with 'Nosean-phonolite' |
Related Minerals - Strunz-mindat Grouping
| 9.DA. | Colomeraite | NaTi3+Si2O6 |
| 9.DA. | Protoenstatite | Mg2Si2O6 |
| 9.DA. | Ryabchikovite | CuMgSi2O6 |
| 9.DA.05 | Donpeacorite | Mn2+MgSi2O6 |
| 9.DA.05 | Enstatite | Mg2Si2O6 |
| 9.DA.05 | Ferrosilite | Fe2+2Si2O6 |
| 9.DA.10 | Clinoenstatite | MgSiO3 |
| 9.DA.10 | Clinoferrosilite | Fe2+2Si2O6 |
| 9.DA.10 | Kanoite | Mn2+MgSi2O6 |
| 9.DA.10 | Pigeonite | (CaxMgyFez)(Mgy1Fez1)Si2O6 |
| 9.DA.15 | Grossmanite | CaTi3+ AlSiO6 |
| 9.DA.15 | Diopside | CaMgSi2O6 |
| 9.DA.15 va | 'Jeffersonite' | Ca(Mn,Zn,Fe)Si2O6 |
| 9.DA.15 | Hedenbergite | CaFe2+Si2O6 |
| 9.DA.15 | Johannsenite | CaMn2+Si2O6 |
| 9.DA.15 | Petedunnite | CaZnSi2O6 |
| 9.DA.15 | Esseneite | CaFe3+[AlSiO6] |
| 9.DA.15 | Kushiroite | CaAlAlSiO6 |
| 9.DA.15 | Augite | (CaxMgyFez)(Mgy1Fez1)Si2O6 |
| 9.DA.15 | Davisite | CaScAlSiO6 |
| 9.DA.20 | Omphacite | (NaaCabFe2+cMgd)(AleFe3+fFe2+gMgh)Si2O6 |
| 9.DA.25 | Jadeite | Na(Al,Fe3+)Si2O6 |
| 9.DA.25 | Namansilite | NaMn3+Si2O6 |
| 9.DA.25 | Natalyite | NaV3+Si2O6 |
| 9.DA.25 | Aegirine | NaFe3+Si2O6 |
| 9.DA.25 | Jervisite | NaSc3+Si2O6 |
| 9.DA.25 | Tissintite | (Ca,◻)AlSi2O6 |
| 9.DA.25 | Kosmochlor | NaCrSi2O6 |
| 9.DA.30 | Spodumene | LiAlSi2O6 |
| 9.DA.35 | Hiroseite | FeSiO3 |
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.
Aegirine-augite in petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Aegirine-augite
mindat.org URL:
https://www.mindat.org/min-32.html
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References for Aegirine-augite
Reference List:
KUNO, Hisashi, TANEDA, Sadakatu (1940) Occurrence of Aegirine-Augite in Some Andesites from Japan. The Journal of the Geological Society of Japan, 47 (557) 62-65 doi:10.5575/geosoc.47.62
Coats, R. R. (1942) Formation of aegirine-augite and arfvedsonite by reaction. Transactions, American Geophysical Union, 23 (2) 347 doi:10.1029/tr023i002p00347-2
King, Basil C. (1962) Optical determination of aegirine-augite with the universal stage. Mineralogical Magazine and Journal of the Mineralogical Society, 33 (257) 132-137 doi:10.1180/minmag.1962.033.257.06
Frondel, Clifford, Ito, Jun (1966) Zincian aegirine-augite and jeffersonite from Franklin, New Jersey. American Mineralogist, 51 (9-10) 1406-1413
Papike, Joan R. Clark arid J. J. (1968) Crystal-chemical characterization of omphacites. American Mineralogist, 53 (5-6) 840-868
Singh, S.K, Bonardi, M (1972) Mössbauer resonance of arfvedsonite and aegirine-augite from the Joan Lake agpaitic complex, Labrador. Lithos, 5 (3) 217-225 doi:10.1016/0024-4937(72)90071-0
Dal Negro, A., Cundari, A., Piccirillo, E. M., Molin, G. M., Uliana, D. (1986) Distinctive crystal chemistry and site configuration of the clinopyroxene from alkali basaltic rocks. Contributions to Mineralogy and Petrology, 92 (1) 35-43 doi:10.1007/bf00373961
Laverne, Christine (1987) Unusual occurrences of aegirine-augite, fassaite and melanite in oceanic basalts (DSDP Hole 504B) Lithos, 20 (2) 135-151 doi:10.1016/0024-4937(87)90003-x
Morimoto, N., Fabries, J., Ferguson, A. K., Ginzburg, I. V., Ross, M., Seifert, F. A., Zussman, J., Aoki, K., Gottardi, G. (1988) Nomenclature of Pyroxenes. Mineralogical Magazine, 52 (367) 535-550 doi:10.1180/minmag.1988.052.367.15
Localities for Aegirine-augite
Showing 844 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.
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Laacher See Volcanic Complex, Germany