Mendigite
A valid IMA mineral species
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About Mendigite
In den Dellen seen from the entrance
In den Dellen quarries, Mendig, Mendig, Mayen-Koblenz, Rhineland-Palatinate, Germany
In den Dellen quarries, Mendig, Mendig, Mayen-Koblenz, Rhineland-Palatinate, Germany
Formula:
Mn2Mn2MnCa(Si3O9)2
Colour:
yellow to brown
Specific Gravity:
3.56 (Calculated)
Crystal System:
Triclinic
Member of:
Name:
Named by N.V. Chukanov, S.M. Aksenov, R.K. Rastsvetaeva, K.V. Van, D.I. Belakovskiy, I.V. Pekov, V.V. Gurzhiy, W. Schüller, and B. Ternes in 2015 after the town of Mendig, near the type locality in Germany.
Type Locality:
Isostructural with:
Unique Identifiers
Mindat ID:
46105
Long-form identifier:
mindat:1:1:46105:8
Similar Names
| Mendipite | A valid IMA mineral species - grandfathered | Pb3Cl2O2 |
| Mindigite | A synonym of Heterogenite |
IMA Classification of Mendigite
Classification of Mendigite
9.00.
9 : SILICATES (Germanates)
0 :
0 :
9 : SILICATES (Germanates)
0 :
0 :
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 |
|---|---|---|
| Mdg | 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 Mendigite
Colour:
Yellow to brown
Comment:
dark brown or black if coated with Mn-oxides
Cleavage:
Perfect
on (001)
on (001)
Density:
3.56 g/cm3 (Calculated)
Optical Data of Mendigite
Type:
Biaxial (-)
RI values:
nα = 1.722 nβ = 1.782(5) nγ = 1.796(5)
2V:
Measured: 50° (10)
Max. Birefringence:
δ = 0.074
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.
Chemistry of Mendigite
Mindat Formula:
Mn2Mn2MnCa(Si3O9)2
Element Weights:
Elements listed:
Crystallography of Mendigite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Setting:
P1
Cell Parameters:
a = 7.0993(4) Å, b = 7.6370(5) Å, c = 7.7037(4) Å
α = 79.58(1)°, β = 62.62(1)°, γ = 76.47(1)°
α = 79.58(1)°, β = 62.62(1)°, γ = 76.47(1)°
Ratio:
a:b:c = 0.93 : 1 : 1.009
Unit Cell V:
359.29 ų
Z:
1
Morphology:
Long-prismatic crystals showing {001} as dominant form, may forming clusters.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.72 Å | (32) |
| 3.40 Å | (20) |
| 3.199 Å | (25) |
| 3.000 Å | (26) |
| 2.885 Å | (100) |
| 2.691 Å | (21) |
| 2.397 Å | (21) |
| 1.774 Å | (37) |
Comments:
From Type Description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 31 : Thermally altered carbonate, phosphate, and iron formations | |
| 32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits |
Type Occurrence of Mendigite
General Appearance of Type Material:
Clusters of long-prismatic crystals (up to 0.1x0.2x2.5 mm in size) in cavities.
Place of Conservation of Type Material:
Type material is deposited in the collections of the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, Russia, registration number 4420/1
Geological Setting of Type Material:
Sandinite
Associated Minerals at Type Locality:
Synonyms of Mendigite
Other Language Names for Mendigite
Relationship of Mendigite to other Species
Member of:
Other Members of Wollastonite Group:
| Barrydawsonite-(Y) | Na1.5Y0.5CaSi3O8(OH) | Mon. 2/m : P21/b |
| Bustamite | CaMn2+(Si2O6) | Tric. 1 : P1 |
| Cascandite | CaScSi3O8(OH) | Tric. 1 |
| Dalnegorskite | Ca5Mn2+(Si3O9)2 | Tric. 1 : P1 |
| Ferrobustamite | CaFe2+(Si2O6) | Tric. 1 |
| Murakamiite | LiCa2Si3O8(OH) | Tric. 1 : P1 |
| Pectolite | NaCa2Si3O8(OH) | Tric. 1 : P1 |
| Schizolite | NaCaMnSi3O8(OH) | Tric. 1 : P1 |
| Serandite | NaMn2+2Si3O8(OH) | Tric. 1 : P1 |
| Tanohataite | LiMn2Si3O8(OH) | Tric. 1 : P1 |
| Vistepite | SnMn4B2Si4O16(OH)2 | Tric. 1 : P1 |
| Wollastonite | Ca3(Si3O9) | Tric. 1 : P1 |
Common Associates
Associations Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 9.00. | Clino-ferri-holmquistite | ◻Li2(Mg3Fe3+2)(Si8O22)(OH)2 |
| 9.00. | Alflarsenite | NaCa2Be3Si4O13(OH) · 2H2O |
| 9.00. | Bridgmanite Subgroup | ABSiO3 |
| 9.00. | Ferroericssonite | BaFe2+2 Fe3+(Si2O7)O(OH) |
| 9.00. | Zvyaginite | NaZnNb2Ti[Si2O7]2(OH,F)3(H2O)4+x (x < 1) |
| 9.00. | Burnettite | CaVAlSiO6 |
| 9.00. | Ferrisepiolite | (Fe3+,Fe2+,Mg)4((Si,Fe3+)6O15)(O,OH)2 · 6H2O |
| 9.00. | Yegorovite | Na4[Si4O8(OH)4] · 7H2O |
| 9.00. | Chrysotile | Mg3(Si2O5)(OH)4 |
| 9.00. | 'Shkatulkalita' | |
| 9.00.15 va | 'Chromoamesite' | Mg2(Al,Cr)(AlSiO5)(OH)4 |
| 9.00.50 | Thornasite | Na12Th4+3(Si8O19)4 · 18H2O |
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 Mendigite
mindat.org URL:
https://www.mindat.org/min-46105.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 Mendigite
Reference List:
Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2014) New minerals and nomenclature modifications approved in 2014, CNMNC Newsletter No 20. Mineralogical Magazine, 78 (3) 549-558 doi:10.1180/minmag.2014.078.3.05
Localities for Mendigite
Showing 7 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.
Germany (TL) | |
| Williams et al. (2014) +1 other reference |
| in the collection of Christof Schäfer |
Spain | |
| Dill et al. (2023) |
| Dill et al. (2023) |
| Dill et al. (2023) | |
| Dill et al. (2023) | |
| Dill et al. (2023) |
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Pumice quarries, Wingertsberg, Mendig, Mendig, Mayen-Koblenz, Rhineland-Palatinate, Germany