Log In
Eckermannite
A valid IMA mineral species
This page is currently not sponsored. Click here to sponsor this page.
About Eckermannite
Harry von Eckermann
Formula:
NaNa2(Mg4Al}Si8O22(OH)2
The eckermannite group minerals are sodium amphiboles defined with A(Na+K+2Ca)> 0.5 apfu and 0.5 apfu < C(Al+Fe3++2Ti) < 1.5 apfu with Al as the dominant element
Eckermannite is defined with
A position: Na dominant
C2+ position: Mg dominant
C3+ position: Al dominant
W position: (OH) dominant
Eckermannite is defined with
A position: Na dominant
C2+ position: Mg dominant
C3+ position: Al dominant
W position: (OH) dominant
Lustre:
Vitreous
Hardness:
5 - 6
Specific Gravity:
3.02 (Calculated)
Crystal System:
Monoclinic
Member of:
Name:
For (Claes Walter) Harry von Eckermann (5 November 1886, Stockholm, Sweden - 20 May 1969, Rönö, Sweden), industrialist, mineralogist and petrologist.
Name first introduced for an amphibole from Norra Kärr, Sweden by Adamson (1942).
Redefined IMA in 2014 (IMA2013-136), according to the new IMA-approved nomenclature of amphiboles published in 2012 (Hawthorne et al., 2012).
NOTE: In the characterization of the holotype of eckermannite from Norra Kärr (Adamson, 1942), Li was not recognized (cf. Sundius 1945). Re-examination of the holotype material and of the original sample analyzed by Törnebohm (1906) confirmed that they both are actually fluoro-leakeite (Oberti et al. 2015). A new holotype for eckermannite, from the Jade Mine Tract, Myanmar, was designated by Oberti et al. (2015).
NOTE: All localities listed here under "eckermannite" should be checked if they are to be assigned to eckermannite according to the redefinition.
Eckermannite is to be expected in metabasites in the post-glaucophane high-P regime (Howe et al., 2018).
Redefined IMA in 2014 (IMA2013-136), according to the new IMA-approved nomenclature of amphiboles published in 2012 (Hawthorne et al., 2012).
NOTE: In the characterization of the holotype of eckermannite from Norra Kärr (Adamson, 1942), Li was not recognized (cf. Sundius 1945). Re-examination of the holotype material and of the original sample analyzed by Törnebohm (1906) confirmed that they both are actually fluoro-leakeite (Oberti et al. 2015). A new holotype for eckermannite, from the Jade Mine Tract, Myanmar, was designated by Oberti et al. (2015).
NOTE: All localities listed here under "eckermannite" should be checked if they are to be assigned to eckermannite according to the redefinition.
Eckermannite is to be expected in metabasites in the post-glaucophane high-P regime (Howe et al., 2018).
Unique Identifiers
Mindat ID:
1348
Long-form identifier:
mindat:1:1:1348:8
IMA Classification of Eckermannite
Approved
IMA status notes:
Renamed by the IMA
IMA Formula:
NaNa2(Mg4Al)Si8O22(OH)2
Approval year:
2013
First published:
1942
Approval history:
Renamed by IMA: 2014
Classification of Eckermannite
9.DE.25
9 : SILICATES (Germanates)
D : Inosilicates
E : Inosilicates with 2-periodic double chains, Si4O11; Clinoamphiboles
9 : SILICATES (Germanates)
D : Inosilicates
E : Inosilicates with 2-periodic double chains, Si4O11; Clinoamphiboles
66.1.3c.6
66 : INOSILICATES Double-Width,Unbranched Chains,(W=2)
1 : Amphiboles - Mg-Fe-Mn-Li subgroup
66 : INOSILICATES Double-Width,Unbranched Chains,(W=2)
1 : Amphiboles - Mg-Fe-Mn-Li subgroup
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 |
|---|---|---|
| Eck | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Eck | Kretz (1983) | Kretz, R. (1983) Symbols of rock-forming minerals. American Mineralogist, 68, 277–279. |
| Eck | 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 |
| Eck | 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 |
| Eck | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Pronunciation of Eckermannite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Eckermannite
Optical Data of Eckermannite
Type:
Biaxial (-)
RI values:
nα = 1.605 nβ = 1.630 nγ = 1.634
Max. Birefringence:
δ = 0.029
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 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.
No measured or calculated 2V is on file for this mineral, so the value used here (43°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
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.
No measured or calculated 2V is on file for this mineral, so the value used here (43°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
r < v moderate
Chemistry of Eckermannite
Mindat Formula:
NaNa2(Mg4Al}Si8O22(OH)2
The eckermannite group minerals are sodium amphiboles defined with A(Na+K+2Ca)> 0.5 apfu and 0.5 apfu < C(Al+Fe3++2Ti) < 1.5 apfu with Al as the dominant element
Eckermannite is defined with
A position: Na dominant
C2+ position: Mg dominant
C3+ position: Al dominant
W position: (OH) dominant
The eckermannite group minerals are sodium amphiboles defined with A(Na+K+2Ca)> 0.5 apfu and 0.5 apfu < C(Al+Fe3++2Ti) < 1.5 apfu with Al as the dominant element
Eckermannite is defined with
A position: Na dominant
C2+ position: Mg dominant
C3+ position: Al dominant
W position: (OH) dominant
Element Weights:
Crystallography of Eckermannite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/m
Setting:
C2/m
Cell Parameters:
a = 9.8087(7) Å, b = 17.845(1) Å, c = 5.2905(4) Å
β = 103.660(1)°
β = 103.660(1)°
Ratio:
a:b:c = 0.55 : 1 : 0.296
Unit Cell V:
899.8 ų
Z:
2
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
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) |
|---|---|---|---|---|---|---|---|
| 0020422 | Eckermannite | Oberti R, Boiocchi M, Hawthorne F C, Ball N A, Harlow G E (2015) Eckermannite revised: The new holotype from the Jade Mine Tract, Myanmar-crystal structure, mineral data, and hints on the reasons for the rarity of eckermannite American Mineralogist 100 909-914 | 2015 | Jade Mine Tract, Kachin Province, Myanmar | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.702 Å | (100) |
| 3.395 Å | (59) |
| 3.128 Å | (56) |
| 2.525 Å | (56) |
| 8.407 Å | (42) |
| 2.574 Å | (36) |
| 3.257 Å | (34) |
| 2.161 Å | (33) |
| 2.966 Å | (33) |
| 4.460 Å | (30) |
Comments:
From Oberti et al. (2015)
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3b: Earth’s earliest hydrosphere | >4.45 |
| 17 : Marine authigenic Hadean minerals (see also #24) | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks | |
| 36 : Carbonatites, kimberlites, and related igneous rocks |
Type Occurrence of Eckermannite
Place of Conservation of Type Material:
In the collections of the Department of Earth and Planetary Sciences, American Museum of Natural History, New York, NY, USA, specimen number AMNH H108401
Synonyms of Eckermannite
Other Language Names for Eckermannite
Relationship of Eckermannite to other Species
Member of:
Other Members of Eckermannite Root Name Group:
| 'Ferro-eckermannite' | NaNa2(Fe2+4Al)Si8O22(OH)2 | Mon. |
| Mangani-eckermannite | NaNa2(Mg4Mn3+)Si8O22(OH)2 | Mon. 2/m : B2/m |
| Mangano-ferri-eckermannite | NaNa2(Mn2+4Fe3+)Si8O22(OH)2 | Mon. 2/m : B2/m |
| Scandio-fluoro-eckermannite | NaNa2(Mg4Sc)(Si8O22)F2 | Mon. 2/m : B2/m |
Common Associates
Associations Based on Photo Data:
| 2 photos of Eckermannite associated with Arfvedsonite | NaNa2(Fe2+4Fe3+)Si8O22(OH)2 |
| 2 photos of Eckermannite associated with Quartz | SiO2 |
| 1 photo of Eckermannite associated with Aegirine | NaFe3+Si2O6 |
| 1 photo of Eckermannite associated with Richterite | Na(CaNa)Mg5(Si8O22)(OH)2 |
| 1 photo of Eckermannite associated with Natrolite | Na2Al2Si3O10 · 2H2O |
| 1 photo of Eckermannite associated with |
Hpakant-Tawmaw Jade Tract, Hpakant Township, Mohnyin District, Kachin State, Myanmar