Namansilite
A valid IMA mineral species
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About Namansilite
Formula:
NaMn3+Si2O6
Colour:
Dark brownish red, purplish red
Lustre:
Adamantine, Vitreous, Pearly
Hardness:
6 - 7
Specific Gravity:
3.51
Crystal System:
Monoclinic
Member of:
Name:
For the principal constituent elements: sodium (natrium), manganese, silicon.
Unique Identifiers
Mindat ID:
2834
Long-form identifier:
mindat:1:1:2834:5
IMA Classification of Namansilite
Approved
Approval year:
1989
Classification of Namansilite
9.DA.25
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
65.1.3c.3
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
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 |
|---|---|---|
| Nms | 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 Namansilite
Adamantine, Vitreous, Pearly
Transparency:
Transparent
Colour:
Dark brownish red, purplish red
Streak:
Brownish violet
Hardness:
6 - 7 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
{110}
{110}
Density:
3.51 g/cm3 (Measured) 3.61 g/cm3 (Calculated)
Optical Data of Namansilite
Type:
Biaxial (-)
RI values:
nα = 1.734 - 1.750 nβ = 1.769 - 1.85 nγ = 1.835 - 1.87
2V:
Measured: 15° to 85°, Calculated: 64°
Max. Birefringence:
δ = 0.101 - 0.120
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
Optical Extinction:
Y = b; X ∧ c = 19°-25°.
Pleochroism:
Strong
Comments:
X = lemon-yellow to pale yellow-orange; Y = raspberry-red to brownish red; Z = blood-red to reddish purple.
Comments:
Absorption: Z > Y > X.
Chemistry of Namansilite
Mindat Formula:
NaMn3+Si2O6
Element Weights:
Elements listed:
Common Impurities:
Al,Ti,Fe,Mg,Ca,K,Sr,Ba
Chemical Analysis
Oxide wt%:
| 1 | |
|---|---|
| SiO2 | 52.57 % |
| TiO2 | 0.02 % |
| Al2O3 | 0.04 % |
| V2O3 | 0.01 % |
| Mn2O3* | 33.67 % |
| Fe2O3* | 0.09 % |
| MgO | 0.74 % |
| CaO | 0.18 % |
| SrO | 0.01 % |
| Na2O | 13.51 % |
| Total: | 100.84 % |
Empirical formulas:
| Sample ID | Empirical Formula |
|---|---|
| 1 | (Na0.99Ca0.01Mg0.01)(Mn3+0.97Mg0.03)[Si1.99O6] |
Sample references:
| ID | Locality | Reference | Notes |
|---|---|---|---|
| 1 | Cerchiara Mine, Borghetto di Vara, La Spezia Province, Liguria, Italy | Acicular namansilite growing into cavity filled with calcite + quartz. Analysis by EPMA. *Fe3+/∑Fe and Mn3+/∑Mn calculated by charge balance, with all Fe assigned to Fe3+ before any Mn is assigned to Mn3+. |
Crystallography of Namansilite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/b
Setting:
C2/c
Cell Parameters:
a = 9.506(6) Å, b = 8.612(2) Å, c = 5.354(2) Å
β = 105.06(6)°
β = 105.06(6)°
Ratio:
a:b:c = 1.104 : 1 : 0.622
Unit Cell V:
423.25 ų (Calculated from Unit Cell)
Z:
4
Twinning:
On {100}, simple; polysynthetic.
Crystal Structure
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2x2x2 | 3x3x3 | 4x4x4
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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) |
|---|---|---|---|---|---|---|---|
| 0010035 | Namansilite | Ohashi H, Osawa T, Tsukimura K (1987) Refinement of the structure of manganese sodium dimetasilicate Acta Crystallographica C43 605-607 |  | 1987 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.925 Å | (100) |
| 2.883 Å | (100) |
| 6.29 Å | (66) |
| 2.499 Å | (50) |
| 2.495 Å | (50) |
| 4.305 Å | (45) |
| 1.579 Å | (24) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits | |
| Stage 7: Great Oxidation Event | <2.4 |
| 47e : [Vanadates, chromates, manganates] | |
| 47h : [Near-surface oxidized, dehydrated minerals] |
Type Occurrence of Namansilite
Co-Type Localities:
General Appearance of Type Material:
Stout prismatic crystals, to 2 mm, forming irregular pods and aggregates.
Place of Conservation of Type Material:
A.E. Fersman Mineralogical Museum, Academy of Sciences, Moscow, Russia.
Geological Setting of Type Material:
Low-grade metamorphosed and highly oxidized Mn, Na-rich sediments.
Associated Minerals at Type Locality:
Synonyms of Namansilite
Other Language Names for Namansilite
Relationship of Namansilite 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+MgSi2O6 | Mon. 2/m : P21/b |
| Kosmochlor | NaCrSi2O6 | Mon. 2/m : B2/b |
| Kushiroite | CaAlAlSiO6 | 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:
| 16 photos of Namansilite associated with Pectolite | NaCa2Si3O8(OH) |
| 14 photos of Namansilite associated with Braunite | Mn2+Mn3+6(SiO4)O8 |
| 6 photos of Namansilite associated with Quartz | SiO2 |
| 4 photos of Namansilite associated with Cerchiaraite-(Mn) | Ba4Mn3+4(Si4O12)O2(OH)4Cl2[Si2O3(OH)4] |
| 4 photos of Namansilite associated with Taikanite | Sr3BaMn2+2(Si4O12)O2 |
| 4 photos of Namansilite associated with Strakhovite | NaBa3Mn2+2Mn3+2Si6O19(OH)3 |
| 3 photos of Namansilite associated with Miyahisaite | (Sr,Ca)2Ba3(PO4)3F |
| 3 photos of Namansilite associated with Aegirine | NaFe3+Si2O6 |
| 3 photos of Namansilite associated with Orientite | Ca8Mn3+10(SiO4)3(Si3O10)3(OH)10 · 4H2O |
| 2 photos of Namansilite associated with Noelbensonite | BaMn3+2(Si2O7)(OH)2 · H2O |
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 | Aegirine-augite | (NaaCabFe2+cMgd)(Fe3+eAlfFe2+gMgh)Si2O6 |
| 9.DA.20 | Omphacite | (NaaCabFe2+cMgd)(AleFe3+fFe2+gMgh)Si2O6 |
| 9.DA.25 | Jadeite | Na(Al,Fe3+)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.
Internet Links for Namansilite
mindat.org URL:
https://www.mindat.org/min-2834.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Namansilite
Reference List:
Ohashi, H., Osawa, T., Tsukimura, K. (1987) Refinement of the structure of manganese sodium dimetasilicate. Acta Crystallographica Section C Crystal Structure Communications, 43 (4) 605-607 doi:10.1107/s0108270187094836
Kawachi, Yosuke; Coombs, Douglas S. (1993) Namansilite, NaMn3+Si2O6: a widespread clinopyroxene? Mineralogical Magazine, 57 (388). 533-538 doi:10.1180/minmag.1993.057.388.15
Localities for Namansilite
Showing 14 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.
Australia | |
| Eggleton et al. (1994) +1 other reference |
| Kawachi et al. (1993) +2 other references |
Germany | |
| Blass et al. (2006) |
Italy | |
| Kawachi et al. (1996) |
Japan | |
| Nishio-Hamane et al. (2012) +1 other reference |
Romania | |
| minerals-of-the-carpathians.eu (2008) |
Russia | |
| Mandarino (1996) |
| Pekov (1998) |
| Pekov (1998) |
South Africa | |
| Gu et al. (2019) |
Spain | |
| Dill et al. (2023) |
| Dill et al. (2023) |
| Dill et al. (2023) | |
| Dill et al. (2023) |
Quick NavTopAbout NamansiliteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Chemical AnalysisCrystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesRelationshipsCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Dzhavodi area, Ir-Nimi manganese deposit, Taikan Ridge, Khabarovsk Krai, Russia