Omphacite
A valid IMA mineral species
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About Omphacite
Green unripe grapes
Formula:
(NaaCabFe2+cMgd)(AleFe3+fFe2+gMgh)Si2O6
a+b+c+d = 1
e+f+g=h = 1
a = e+f
0.2 ≤ a ≤ 0.8
e > f
e+f+g=h = 1
a = e+f
0.2 ≤ a ≤ 0.8
e > f
Colour:
Dark green
Hardness:
5 - 6
Crystal System:
Monoclinic
Member of:
Name:
From the Greek for unripe grape, in allusion to its green colour.
A clinopyroxene intermediate between jadeite and augite, with solid solution towards aegirine-augite. There is a solvus between omphacite (P2/n) and jadeite (C2/c) and also between omphacite and augite/diopside (C2/c), below about 500°C. Above this temperature there may be complete solid solution with a disordered C2/c structure. Note the classification diagram of Morimoto does not quite fit the structural changes: some minerals with the jadeite C2/c structure plot in Morimoto’s omphacite field, which should be P2/n below about 500°C.
The Ca analogue of UM2001-19-SiO:AlCaMgNa -possibly the Na-dominant “omphacite” with the C2/c structure?
A primary constituent of the high pressure and temperature rock eclogite.
May contain trace water in form of structurally-bound hydroxyl groups. As an example, omphacite from Pohorje Mts., Slovenia, has 530 to 870 ppm H2O (Skogby et al., 2016).
Visit gemdat.org for gemological information about Omphacite.
The Ca analogue of UM2001-19-SiO:AlCaMgNa -possibly the Na-dominant “omphacite” with the C2/c structure?
A primary constituent of the high pressure and temperature rock eclogite.
May contain trace water in form of structurally-bound hydroxyl groups. As an example, omphacite from Pohorje Mts., Slovenia, has 530 to 870 ppm H2O (Skogby et al., 2016).
Visit gemdat.org for gemological information about Omphacite.Unique Identifiers
Mindat ID:
2991
Long-form identifier:
mindat:1:1:2991:5
Classification of Omphacite
Accepted names for Na pyroxenes (after Morimoto et al, 1988)
IMA Classification of Omphacite
Approved
IMA Formula:
(Ca,Na)(Mg,Fe,Al)Si2O6
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.1
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
16.24.2
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 |
|---|---|---|
| Omp | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Omp | Kretz (1983) | Kretz, R. (1983) Symbols of rock-forming minerals. American Mineralogist, 68, 277–279. |
| Omp | 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 |
| Omp | 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 |
| Omp | 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 Omphacite
Optical Data of Omphacite
Type:
Biaxial (+)
RI values:
nα = 1.662 - 1.701 nβ = 1.67 - 1.712 nγ = 1.685 - 1.723
2V:
Measured: 58° to 83°, Calculated: 74° to 88°
Max. Birefringence:
δ = 0.022 - 0.023
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.
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.
Surface Relief:
Moderate
Dispersion:
r > v moderate
Chemistry of Omphacite
Mindat Formula:
(NaaCabFe2+cMgd)(AleFe3+fFe2+gMgh)Si2O6
a+b+c+d = 1
e+f+g=h = 1
a = e+f
0.2 ≤ a ≤ 0.8
e > f
a+b+c+d = 1
e+f+g=h = 1
a = e+f
0.2 ≤ a ≤ 0.8
e > f
Common Impurities:
Ti,Cr,Mn,K,H2O
Chemical Analysis
Oxide wt%:
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| SiO2 | 56.63 % | 55.02 % | 55.43 % | 54.31 % | 54.54 % | 53.64 % | 56.59 % | 55.02 % | 54.89 % | 55.41 % | 55.97 % | 55.11 % | 54.50 % | 54.44 % | 55.75 % |
| TiO2 | 0.09 % | .05 % | 0.07 % | 0.02 % | 0.08 % | 0.16 % | 0.14 % | 0.07 % | 0.07 % | 0.13 % | 0.2 % | 0.10 % | |||
| Al2O3 | 14.94 % | 4.25 % | 10.05 % | 9.98 % | 10.18 % | 11.88 % | 12.46 % | 12.8 % | 9.29 % | 11.31 % | 10.36 % | 5.88 % | 11.45 % | 9.67 % | 11.50 % |
| FeO | 7.22 % | 4.76 % | 2.94 % | 1.84 % | 2.47 % | 2.56 % | 6.60 % | 3.52 % | 7.20 % | 5.05 % | |||||
| MnO | .13 % | 0.02 % | 0.05 % | 0.03 % | 0.05 % | 0.09 % | 0.19 % | 0.04 % | 0.03 % | 0.13 % | |||||
| MgO | 3.45 % | 13.24 % | 10.4 % | 10.69 % | 10.00 % | 9.44 % | 8.29 % | 6.83 % | 7.47 % | 6.31 % | 9.45 % | 10.20 % | 9.28 % | 9.29 % | 8.21 % |
| CaO | 6.26 % | 19.82 % | 16.26 % | 16.13 % | 14.78 % | 15.07 % | 12.16 % | 11.74 % | 14.67 % | 11.57 % | 14.07 % | 16.45 % | 15.20 % | 15.81 % | 13.29 % |
| Na2O | 11.05 % | 3.28 % | 5.43 % | 5.5 % | 5.7 % | 5.77 % | 7.42 % | 6.99 % | 5.93 % | 8.01 % | 6.49 % | 5.18 % | 5.79 % | 5.44 % | 6.67 % |
| K2O | .00 % | 0.03 % | 0.02 % | 0.00 % | nd % | 0.00 % | |||||||||
| Cr2O3 | .01 % | 0.00 % | 0.04 % | 0.14 % | 0.10 % | 0.05 % | 0.05 % | ||||||||
| FeOT | 3.33 % | 6.17 % | 6.79 % | ||||||||||||
| FeOt | 3.56 % | 4.77 % | |||||||||||||
| Total: | 99.64 % | 100.56 % | 100.6 % | 98.47 % | 97.8 % | 98.55 % | 100.25 % | 99.55 % | 99.04 % | 99.47 % | 100.18 % | 100.38 % | 100 % | 99.93 % | 100.47 % |
Empirical formulas:
| Sample ID | Empirical Formula |
|---|---|
| 7 | (Na0.51Ca0.46Fe2+0.03) (Al0.50Fe3+0.01 Fe2+0.05 Mg0.44) Si2O6 |
| 8 | (Na0.49Ca0.45Fe2+0.06) Σ 1.00 (Al0.54Fe2+0.13 Mg0.33) Σ 1.00 Si1.97O6 |
| 9 | (Na0.42Ca0.57Fe2+0.02) Σ 1.01 (Al0.40Fe3+0.02 Mg0.41 Fe2+0.17) Σ 1.00 Si2.00O6 |
| 10 | (Na0.45Ca0.57Fe2+0.02 Mn2+0.02) Σ 1.06 (Al0.48Mg0.34 Fe2+0.18) Σ 1.00 Si2.00O6 |
| 11 | (Na0.45Ca0.53Fe0.03) Σ 1.01 (Al0.43Mg0.50 Fe0.07) Σ 1.00 Si1.98O6 |
| 12 | (Na0.36Ca0.63Fe0.03) Σ 1.01 (Al0.25Mg0.55 Fe0.22) Σ 1.00 Si1.98O6 |
| 13 | (Na0.40Ca0.58Fe0.02)Σ1.00 (Mg0.49Fe2+0.05Fe3+0.04Al0.42) Σ 1.00 (Al0.06Si1.94)O6 |
| 14 | (Na0.38 Ca0.61 Fe2+0.03) Σ 1.01 (Al0.41 Mg0.50 Fe2+0.02 Fe3+0.06 Ti0.01) Σ 1.00 Si1.95O6 |
| 15 | (Na0.46Ca0.50Fe2+0.05)Σ1.01(Al0.48Mg0.43 Fe2+0.07Fe3+0.02) Σ 1.00 Si1.98O6 |
Sample references:
| ID | Locality | Reference | Notes |
|---|---|---|---|
| 1 | Yingshan, Yingshan Co., Huanggang, Hubei, China | The sample mainly comprise eclogite with garnet and omphacite. Other main constituent minerals are amphibole, epidote, quartz, phengite, kyanite, and rutile. Fine–grained(<1-3µm) symplectite of clinopyroxene+plagioclase partially replaces omphacite Quantitative analyses of major elements were performed using wavelength–dispersive X–ray spectrometry at Okayama University(JEOLJXA–8230). A 15–kV accelerating potential and a 20–nA beam current were employed in the analyses. | |
| 2 | Kesandere valley eclogites, Bitlis Province, Turkey | EMPA analysis of omphacite from an eclogite | |
| 3 | Gablor Hill eclogites, Kulp district, Diyarbakir Province, Turkey | fine-grained dark blasts from the ground mass in a kyanite-eclogite, EMPA analysis | |
| 4 | " " | Analysis of fine grained (0.5-1mm) omphacite from the matrix of a quartz bearing kyanite-eclogite.EMPA analysis | |
| 5 | " " | Analysis of fine grained (0.5-1mm) omphacite from the matrix of a quartz-eclogite. EMPA analysis | |
| 6 | Danmarkshavn eclogites, Danmarkshavn, Northeast Greenland National Park, Greenland | Clinopyroxene from a kyanite-eclogite. | |
| 7 | Charakoma eclogite, Soufli, Evros, Eastern Macedonia and Thrace, Greece | EMPA analysis of a matrix omphacite in a kyanite-eclogite | |
| 8 | " " | EMPA analysis of a omphacite inclusion in an almandine garnet porphyroblast from a kyanite-eclogite | |
| 9 | Kovalo eclogites, Kechros, Arriana, Rhodope, Eastern Macedonia and Thrace, Greece | EMPA analysis of matrix omphacite from an eclogite. | |
| 10 | Eissee eclogite, Timmelbach valley, Prägraten am Großvenediger, Lienz District, Tyrol, Austria | EMPA analysis of omphacite blade (<5mm) in contact with garnet ( sample ga6/27 - see almandine) in a kyanite-eclogite. All Fe estimated as Fe2+. | |
| 11 | Steinsteg eclogite, Frosnitz valley, Matrei in Osttirol, Lienz District, Tyrol, Austria | EMPA analysis green omphacite (0.2mm) from the matrix of a kyanite-eclogite | |
| 12 | " " | EMPA analysis of an omphacite inclusion in garnet from a post eclogite facies mica schist. | |
| 13 | Nogva eclogite outcrop, Flemsøya-Skuløya, Haram, Ålesund, Møre og Romsdal, Norway | EMPA analysis (University of Massachusetts) of omphacite from an eclogite | |
| 14 | Hohl-Felsen eclogite, Wernersdorf, Wies, Deutschlandsberg District, Styria, Austria | Omphacite commonly occurs as small anhedral, oriented grains (~3mm) in the eclogite matrix, but is less common in the eclogitic veins. The chemistry of omphacite in the eclogite and in the eclogitic veins are very similar. | |
| 15 | Obidim eclogite, Bansko Municipality, Blagoevgrad Province, Bulgaria | EMPA analysis ( State Geological Institute of Dionyz Stur in Bratislava).of an omphacite inclusion in garnet from a kyanite-eclogite |
Crystallography of Omphacite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Cell Parameters:
a = 9.66 Å, b = 8.81 Å, c = 5.22 Å
β = 106.56°
β = 106.56°
Ratio:
a:b:c = 1.096 : 1 : 0.593
Unit Cell V:
425.82 ų (Calculated from Unit Cell)
Comment:
Space group may be C2/c or P2/n.
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) |
|---|---|---|---|---|---|---|---|
| 0000175 | Omphacite | Clark J R, Papike J J (1968) Crystal-chemical characterization of omphacites American Mineralogist 53 840-868 |  | 1968 | 0 | 293 | |
| 0000466 | Omphacite | Matsumoto T, Tokonami M, Morimoto N (1975) The crystal structure of omphacite American Mineralogist 60 634-641 | | 1975 | 0 | 293 | |
| 0001054 | Omphacite | McCormick T C (1986) Crystal-chemical aspects of nonstoichiometric pyroxenes American Mineralogist 71 1434-1440 | | 1986 | 0 | 293 | |
| 0001055 | Omphacite | McCormick T C (1986) Crystal-chemical aspects of nonstoichiometric pyroxenes American Mineralogist 71 1434-1440 | | 1986 | 0 | 293 | |
| 0001056 | Omphacite | McCormick T C (1986) Crystal-chemical aspects of nonstoichiometric pyroxenes American Mineralogist 71 1434-1440 | | 1986 | 0 | 293 | |
| 0005103 | Omphacite | Curtis L, Gittins J, Kocman V, Rucklidge J C, Hawthorne F C, Ferguson R B (1975) Two crystal structure refinements of a P2/n titanian ferro-omphacite The Canadian Mineralogist 13 62-67 | | 1975 | 0 | 293 | |
| 0005104 | Omphacite | Curtis L, Gittins J, Kocman V, Rucklidge J C, Hawthorne F C, Ferguson R B (1975) Two crystal structure refinements of a P2/n titanian ferro-omphacite The Canadian Mineralogist 13 62-67 | | 1975 | 0 | 293 | |
| 0014547 | Omphacite | Pavese A, Bocchio R, Ivaldi G (2000) In situ high temperature single crystal X-ray diffraction study of a natural omphacite Mineralogical Magazine 64 983-993 | | 2000 | Gorduno, Lepontine Alps, Switzerland | 0 | 293 |
| 0014548 | Omphacite | Pavese A, Bocchio R, Ivaldi G (2000) In situ high temperature single crystal X-ray diffraction study of a natural omphacite Mineralogical Magazine 64 983-993 | | 2000 | Gorduno, Lepontine Alps, Switzerland | 0 | 293 |
| 0014549 | Omphacite | Pavese A, Bocchio R, Ivaldi G (2000) In situ high temperature single crystal X-ray diffraction study of a natural omphacite Mineralogical Magazine 64 983-993 | | 2000 | Gorduno, Lepontine Alps, Switzerland | 0 | 293 |
| 0015676 | Omphacite | Mottana A, Rossi G, Kracher A, Kurat G (1979) Violan revisited: Mn-bearing omphacite and diopside Tschermaks Mineralogische und Petrographische Mitteilungen 26 187-201 | 1979 | manganese deposit of Praborna, St Marcel, Aosta Valley, Italy | 0 | 293 |
CIF Raw Data - click here to close
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3a: Earth’s earliest Hadean crust | >4.50 |
| 7 : Ultramafic igneous rocks | |
| Stage 3b: Earth’s earliest hydrosphere | >4.45 |
| 12 : Hadean hydrothermal subsurface sulfide deposits (see also #33) | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 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) |
Type Occurrence of Omphacite
Synonyms of Omphacite
Other Language Names for Omphacite
Varieties of Omphacite
| Chrome-Omphacite | A chrome-rich variety of Omphacite |
| Titanium-bearing Omphacite | An omphacite with at least 0.10 Ti4+ cations in the M1 position in the clinopyroxene structure. Additional Na+ cations replacing divalent cations in the M2 position are needed to obtain charge balance. |
Relationship of Omphacite to other Species
Member of:
Other Members of Clinopyroxene Subgroup:
| Aegirine | NaFe3+Si2O6 | Mon. 2/m : B2/b |
| Aegirine-augite | (NaaCabFe2+cMgd)(Fe3+eAlfFe2+gMgh)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+(Mg,Mn2+)Si2O6 | 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 |
| 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 |
| UM2001-19-SiO:AlCaMgNa | (Na,Mg,Ca)(Mg,Al)Si2O6 | Mon. 2/m : B2/b |
| UM2003-36-SiO:CaNa | NaCrSi2O6 - CaMgSi2O6 | Mon. 2/m : B2/b |
Common Associates
Associated Minerals Based on Photo Data:
| 27 photos of Omphacite associated with Garnet Group | X3Z2(SiO4)3 |
| 12 photos of Omphacite associated with Kyanite | Al2(SiO4)O |
| 10 photos of Omphacite associated with Glaucophane | ◻[Na2][Mg3Al2]Si8O22(OH)2 |
| 10 photos of Omphacite associated with Almandine | Fe2+3Al2(SiO4)3 |
| 8 photos of Omphacite associated with Pyrope | Mg3Al2(SiO4)3 |
| 5 photos of Omphacite associated with Eclogite | |
| 5 photos of Omphacite associated with Ruby | Al2O3 |
| 4 photos of Omphacite associated with Titanite | CaTi(SiO4)O |
| 4 photos of Omphacite associated with Quartz | SiO2 |
| 4 photos of Omphacite associated with Kumdykolite | Na(AlSi3O8) |
Related Minerals - Strunz-mindat Grouping
| 9.DA. | Colomeraite | NaTi3+Si2O6 |
| 9.DA. | Protoenstatite | Mg2Si2O6 |
| 9.DA. | Ryabchikovite | CuMgSi2O6 |
| 9.DA.05 | Donpeacorite | (Mn,Mg)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+(Mg,Mn2+)Si2O6 |
| 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 | Aegirine-augite | (NaaCabFe2+cMgd)(Fe3+eAlfFe2+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.
Omphacite in petrology
An essential component of rock names highlighted in red, an accessory component in rock names highlighted in green.
Internet Links for Omphacite
mindat.org URL:
https://www.mindat.org/min-2991.html
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References for Omphacite
Reference List:
Werner, Abraham Gottlob (1817) Letztes Mineral-System - Aus dessen Nachlasse auf oberbergamtliche Anordnung herausgegeben und mit Erläuterungen versehen.pages 33-34 and 42-43
Warner, Jeffrey (1964) X-ray crystallography of omphacite. American Mineralogist, 49 (9-10) 1461-1466
Papike, Joan R. Clark arid J. J. (1968) Crystal-chemical characterization of omphacites. American Mineralogist, 53 (5-6) 840-868
Edgar, A. D., Mottana, A., Macrae, N. D. (1969) The chemistry and cell parameters of omphacites and related pyroxenes. Mineralogical Magazine, 37 (285) 61-74 doi:10.1180/minmag.1969.037.285.07
Champness, Pamela E. (1973) Speculation on an order-disorder transformation in omphacite. American Mineralogist, 58 (5-6) 540-542
Matsumoto, Takeo, Tokonami, Masayasu, Morimoto, Nobuo (1975) The crystal structure of omphacite. American Mineralogist, 60 (7-8) 634-641
Aldridge, L. P., Bancroft, G. M., Fleet, M. E., Herzberg, C. T. (1978) Omphacite studies, II. Mössbauer spectra of C2/c and P2/n omphacites. American Mineralogist, 63 (11-12) 1107-1115
Mottana, A., Rossi, G., Kracher, A., Kurat, G. (1979) Violan revisited: Mn-bearing omphacite and diopside. TMPM Tschermaks Mineralogische und Petrographische Mitteilungen, 26 (3). 187-201 doi:10.1007/bf01081845
Camara, Fernando, Nieto, Fernando, Oberti, Roberta (1998) Effects of Fe2+ and Fe3+ contents on cation ordering in omphacite. European Journal of Mineralogy, 10 (5) 889-906 doi:10.1127/ejm/10/5/0889
Schmädicke, Esther; Müller, Wolfgang Friedrich (2000) Unusual exsolution phenomena in omphacite and partial replacement of phengite by phlogopite + kyanite in an eclogite from the Erzgebirge. Contributions to Mineralogy and Petrology, 139 (6). 629-642 doi:10.1007/s004100000161
Katerinopoulou, A., Katerinopoulos, A., Bieniok, A., Knop, E., Magganas, A., Amthauer, G. (2007) Crystal chemistry, structure analyses and phase transition experiment on an omphacite from eclogitic metagabbro from Syros island, Greece. Mineralogy and Petrology, 91 (1) 117-128 doi:10.1007/s00710-007-0185-5
Green, E., Holland, T., Powell, R. (2007) An order-disorder model for omphacitic pyroxenes in the system jadeite-diopside-hedenbergite-acmite, with applications to eclogitic rocks. American Mineralogist, 92 (7) 1181-1189 doi:10.2138/am.2007.2401
McNamara, David D. (2012) Omphacite-a mineral under pressure!. Geology Today, 28 (2) 71-75 doi:10.1111/j.1365-2451.2012.00830.x
Cárdenas-Párraga, Juan, García-Casco, Antonio, Harlow, George E., Blanco-Quintero, Idael Francisco, Agramonte, Yamirka Rojas, Kröner, Alfred (2012) Hydrothermal origin and age of jadeitites from Sierra del Convento Mélange (Eastern Cuba) European Journal of Mineralogy, 24 (2) 313-331 doi:10.1127/0935-1221/2012/0024-2171
Skogby, Henrik, Janák, Marian, Broska, Igor (2016) Water incorporation in omphacite: concentrations and compositional relations in ultrahigh-pressure eclogites from Pohorje, Eastern Alps. European Journal of Mineralogy, 28 (3) 631-639 doi:10.1127/ejm/2016/0028-2533
Jiang, Peilin, Liu, Hanyong, Skogby, Henrik, Chen, Ren-Xu, Yang, Xiaozhi (2022) Water in omphacite fingerprints the thermal history of eclogites. Geology, 50 (3) 316-320 doi:10.1130/g49566.1
www.digitale-sammlungen.de (2023) https://www.digitale-sammlungen.de/de/view/bsb10706805?q=%28omphax&page=48,49
Li, Ting; Zhang, Cun; Lv, Linsu; Zhang, Haitao; Chen, Yuqing; Li, Zhibin; Liu, Yue (2023) Color-Causing Mechanisms of Guatemala Jadeite Jade: Constraints from Spectroscopy and Chemical Compositions. Crystals, 13 (11). 1535 doi:10.3390/cryst13111535
Baratelli, Lisa, Murri, Mara, Alvaro, Matteo, Prencipe, Mauro, Mihailova, Boriana, Cámara, Fernando (2024) Raman scattering of omphacite at high pressure: Toward its possible application to elastic geothermobarometry. American Mineralogist, 109 (12). doi:10.2138/am-2023-9140
Gong, Ting-Nan, Du, Jin-Xue, Zhang, Li-Fei, Chen, Zhen-Yu, Zhang, Ze-Ming, Wang, Wei-(RZ), Qu, Yuan-Ru (2025) Mineral precipitation sequence from multi-stage fluids released by eclogite during high-pressure metamorphism. American Mineralogist, 110 (1). 136-153 doi:10.2138/am-2023-9218(omphacite vein formed in eclogite)
Localities for Omphacite
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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Bric Vert, Quincinetto, Metropolitan City of Turin, Piedmont, Italy