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Nikmelnikovite
A valid IMA mineral species
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Nikolai N. Melnikov
Formula:
Ca12(Fe2+Fe3+3Al3◻)[SiO4]6[◻(OH)4]5◻4
The formula includes "O" vacancies, VI-site vacancies (in the "Y4" site, using traditional garnet site nomenclature), and IV-site vacancies (in the "Z2" site, using traditional garnet site nomenclature; each missing Si is charge-balanced by four H, as the "hydrogarnet" exchange).
The VI-site occupancy in the original end-member formula was given as (Fe2+Fe3+2Al4◻), but this was changed to (Fe2+Fe3+3Al3◻) in Bosi et al., (2019).
The VI-site occupancy in the original end-member formula was given as (Fe2+Fe3+2Al4◻), but this was changed to (Fe2+Fe3+3Al3◻) in Bosi et al., (2019).
Colour:
Brown to red
Lustre:
Vitreous, Greasy
Hardness:
5½
Specific Gravity:
3.00
Crystal System:
Trigonal
Member of:
Name:
In honor of Academician Nikolai Nikolaevich Melnikov (Николай Николаевич Мельников) (25 July 1938, Moscow, USSR – 2 June 2018, Russia), an outstanding mining engineer and science organizer, director of the Mining Institute, Kola Science Center, Russian Academy of Sciences (1981–2015).
Type Locality:
The only trigonal member of the garnet supergroup.
Unique Identifiers
Mindat ID:
53354
Long-form identifier:
mindat:1:1:53354:0
IMA Classification of Nikmelnikovite
Approved
IMA Formula:
Ca12Fe2+Fe3+3Al3(SiO4)6(OH)20
Approval year:
2018
First published:
2019
Type description reference:
Krivovichev, S. V., Yakovenchuk, V. N., Panikorovskii, T. L., Savchenko, E. E., Pakhomovsky, Ya. A., Mikhailova, Yu. A., Selivanova, E. A., Kadyrova, G. I., Ivanyuk, G. Yu. (2019) Nikmelnikovite, Ca12Fe2+Fe3+3Al3(SiO4)6(OH)20: A New Mineral from the Kovdor Massif (Kola Peninsula, Russia) Doklady Earth Sciences, 488 (2) 1200-1202 doi:10.1134/s1028334x19100143
Classification of Nikmelnikovite
9.AD.25
9 : SILICATES (Germanates)
A : Nesosilicates
D : Nesosilicates without additional anions; cations in [6] and/or greater coordination
9 : SILICATES (Germanates)
A : Nesosilicates
D : Nesosilicates without additional anions; cations in [6] and/or greater coordination
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 |
|---|---|---|
| Nmn | 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 Nikmelnikovite
Vitreous, Greasy
Transparency:
Translucent
Colour:
Brown to red
Hardness:
5½ on Mohs scale
Tenacity:
Fragile
Cleavage:
None Observed
Fracture:
Conchoidal
Density:
3.00(3) g/cm3 (Measured) 3.08 g/cm3 (Calculated)
Optical Data of Nikmelnikovite
Type:
Uniaxial
RI values:
nω = 1.682(5) nε = 1.675(5)
Max. Birefringence:
δ = 0.007
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 uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Pleochroism:
Non-pleochroic
Chemistry of Nikmelnikovite
Mindat Formula:
Ca12(Fe2+Fe3+3Al3◻)[SiO4]6[◻(OH)4]5◻4
The formula includes "O" vacancies, VI-site vacancies (in the "Y4" site, using traditional garnet site nomenclature), and IV-site vacancies (in the "Z2" site, using traditional garnet site nomenclature; each missing Si is charge-balanced by four H, as the "hydrogarnet" exchange).
The VI-site occupancy in the original end-member formula was given as (Fe2+Fe3+2Al4◻), but this was changed to (Fe2+Fe3+3Al3◻) in Bosi et al., (2019).
The formula includes "O" vacancies, VI-site vacancies (in the "Y4" site, using traditional garnet site nomenclature), and IV-site vacancies (in the "Z2" site, using traditional garnet site nomenclature; each missing Si is charge-balanced by four H, as the "hydrogarnet" exchange).
The VI-site occupancy in the original end-member formula was given as (Fe2+Fe3+2Al4◻), but this was changed to (Fe2+Fe3+3Al3◻) in Bosi et al., (2019).
Element Weights:
Crystallography of Nikmelnikovite
Crystal System:
Trigonal
Class (H-M):
3 - Rhombohedral
Space Group:
R3
Cell Parameters:
a = 17.2072(6) Å, c = 10.5689(4) Å
Ratio:
a:c = 1 : 0.614
Unit Cell V:
2,710.07 ų (Calculated from Unit Cell)
Z:
3
Twinning:
Merohedral twins by (110) are typical
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.57 Å | (65) |
| 3.042 Å | (58) |
| 2.720 Å | (100) |
| 2.483 Å | (27) |
| 2.223 Å | (28) |
| 1.975 Å | (30) |
| 1.687 Å | (31) |
| 1.626 Å | (32) |
Reference:
Krivovichev, S. V., Yakovenchuk, V. N., Panikorovskii, T. L., Savchenko, E. E., Pakhomovsky, Ya. A., Mikhailova, Yu. A., Selivanova, E. A., Kadyrova, G. I., Ivanyuk, G. Yu. (2019) Nikmelnikovite, Ca12Fe2+Fe3+3Al3(SiO4)6(OH)20: A New Mineral from the Kovdor Massif (Kola Peninsula, Russia) Doklady Earth Sciences, 488 (2) 1200-1202 doi:10.1134/s1028334x19100143
Comments:
From Type Description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] |
Type Occurrence of Nikmelnikovite
General Appearance of Type Material:
Overgrows octahedral faces of crystals of andradite impregnated in calcite, as semitransparent brownish red crusts (<=1 mm thick), rhombohedral crystals to 100 microns, and spherical globules to 5 microns.
Place of Conservation of Type Material:
Type material is deposited in the collections of the Mineralogical Museum, St. Petersburg State University, Russia, catalogue No. 1/19691
Associated Minerals at Type Locality:
Reference:
Krivovichev, S. V., Yakovenchuk, V. N., Panikorovskii, T. L., Savchenko, E. E., Pakhomovsky, Ya. A., Mikhailova, Yu. A., Selivanova, E. A., Kadyrova, G. I., Ivanyuk, G. Yu. (2019) Nikmelnikovite, Ca12Fe2+Fe3+3Al3(SiO4)6(OH)20: A New Mineral from the Kovdor Massif (Kola Peninsula, Russia) Doklady Earth Sciences, 488 (2) 1200-1202 doi:10.1134/s1028334x19100143
Synonyms of Nikmelnikovite
Other Language Names for Nikmelnikovite
Dutch:Nikmelnikoviet
German:Nikmelnikovit
Relationship of Nikmelnikovite to other Species
Member of:
Other Members of Garnet Supergroup:
| Berzeliite Group | X3Z2[TO4]3 | |
| Bitikleite Group | Ca3Z2[TO4]3 | |
| Cryolithionite | Na3Al2(LiF4)3 | Iso. m3m(4/m32/m) : Ia3d |
| Garnet Group | X3Z2(SiO4)3 | |
| Henritermierite Group | Ca3Z2(SiO4)2[◻(OH)4] | |
| Katoite | Ca3Al2[◻(OH)4]3 | Iso. m3m(4/m32/m) : Ia3d |
| Midbarite | Ca3Mg2(V5+2Si)O12 | Iso. m3m(4/m32/m) : Ia3d |
| Monteneveite | Ca3Sb5+2(Fe3+2Fe2+)O12 | Iso. m3m(4/m32/m) : Ia3d |
| Priscillagrewite-(Y) | (Ca2Y)Zr2(AlO4)3 | Iso. |
| Schorlomite Group | Ca3Z2[SiO4][TO4]2 | |
| Xuite | Ca3Fe3+2[(AlO3(OH)]3 | Iso. m3m(4/m32/m) |
| Yafsoanite | Ca3Te6+2(ZnO4)3 | Iso. m3m(4/m32/m) : Ia3d |
Related Minerals - Strunz-mindat Grouping
| 9.AD. | Adrianite | Ca12(Al4Mg3Si7)O32Cl6 |
| 9.AD.05 | Larnite | Ca2SiO4 |
| 9.AD.10 | Calcio-olivine | Ca2SiO4 |
| 9.AD.15 | Merwinite | Ca3Mg(SiO4)2 |
| 9.AD.20 | Bredigite | Ca7Mg(SiO4)4 |
| 9.AD.25 | Midbarite | Ca3Mg2(V5+2Si)O12 |
| 9.AD.25 | Menzerite-(Y) | (Y2Ca)Mg2(SiO4)3 |
| 9.AD.25 | Uvarovite | Ca3Cr3+2(SiO4)3 |
| 9.AD.25 | Eltyubyuite | Ca12Fe3+10Si4O32Cl6 |
| 9.AD.25 | Eringaite | Ca3Sc2(SiO4)3 |
| 9.AD.25 | Henritermierite | Ca3Mn3+2(SiO4)2[◻(OH)4] |
| 9.AD.25 va | 'Hydrougrandite' | (Ca,Mg,Fe2+)3(Fe3+,Al)2[(OH)4(SiO4)2] |
| 9.AD.25 | Calderite | Mn2+3Fe3+2(SiO4)3 |
| 9.AD.25 | Hutcheonite | Ca3Ti2(SiO4)(AlO4)2 |
| 9.AD.25 | Wadalite | (Ca,Mg)6(Al,Fe3+)4((Si,Al)O4)3O4Cl3 |
| 9.AD.25 | Rubinite | Ca3Ti3+2(SiO4)3 |
| 9.AD.25 | Kerimasite | Ca3Zr2(SiO4)(Fe3+O4)2 |
| 9.AD.25 | Holtstamite | Ca3Al2(SiO4)2[◻(OH)4] |
| 9.AD.25 | Spessartine | Mn2+3Al2(SiO4)3 |
| 9.AD.25 | Toturite | Ca3Sn2(SiO4)(Fe3+O4)2 |
| 9.AD.25 | Kimzeyite | Ca3Zr2(SiO4)(AlO4)2 |
| 9.AD.25 | 'Khoharite' | Mg3Fe3+2(SiO4)3 |
| 9.AD.25 | Irinarassite | Ca3Sn2(SiO4)(AlO4)2 |
| 9.AD.25 | Knorringite | Mg3Cr3+2(SiO4)3 |
| 9.AD.25 | Goldmanite | Ca3V3+2(SiO4)3 |
| 9.AD.25 | 'Blythite' | Mn2+3Mn3+2[SiO4]3 |
| 9.AD.25 | 'Skiagite' | Fe2+3Fe3+2[SiO4]3 |
| 9.AD.25 | 'UM1984-37-SiO:CrMn' | Mn2+3Cr3+2(SiO4)3 |
| 9.AD.25 | Almandine | Fe2+3Al2(SiO4)3 |
| 9.AD.25 va | 'Yamatoite' | (Mn2+,Ca)3(V3+,Al)2(SiO4)3 |
| 9.AD.25 | Momoiite | Mn2+3V3+2(SiO4)3 |
| 9.AD.25 | Grossular | Ca3Al2(SiO4)3 |
| 9.AD.25 | Andradite | Ca3Fe3+2(SiO4)3 |
| 9.AD.25 | Morimotoite | Ca3(TiFe2+)(SiO4)3 |
| 9.AD.25 | Majorite | Mg3(MgSi)(SiO4)3 |
| 9.AD.25 | Pyrope | Mg3Al2(SiO4)3 |
| 9.AD.25 | Schorlomite | Ca3Ti2(SiO4)(Fe3+O4)2 |
| 9.AD.30 | Hafnon | Hf(SiO4) |
| 9.AD.30 | Zircon | Zr(SiO4) |
| 9.AD.30 | Coffinite | U(SiO4) · nH2O |
| 9.AD.30 | Thorite | Th(SiO4) |
| 9.AD.30 va | 'Auerlite' | near Th(Si,P)O4 |
| 9.AD.30 | Stetindite-(Ce) | Ce4+SiO4 |
| 9.AD.35 | 'Tombarthite-(Y)' | Y4(Si,H4)4O12-x(OH)4+2x |
| 9.AD.35 | Huttonite | ThSiO4 |
| 9.AD.40 | Eulytine | Bi4(SiO4)3 |
| 9.AD.45 | Reidite | Zr(SiO4) |
| 9.AD.55 | Jeffbenite | Mg3Al2Si3O12 |
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 Nikmelnikovite
mindat.org URL:
https://www.mindat.org/min-53354.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Nikmelnikovite
Reference List:
Miyawaki, Ritsuro, Hålenius, Ulf, Hatert, Frédéric, Pasero, Marco, Mills, Stuart J. (2019) IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) NEWSLETTER 47. European Journal of Mineralogy, 31 (1) 197-202 doi:10.1127/ejm/2019/0031-2839
Krivovichev, S. V., Yakovenchuk, V. N., Panikorovskii, T. L., Savchenko, E. E., Pakhomovsky, Ya. A., Mikhailova, Yu. A., Selivanova, E. A., Kadyrova, G. I., Ivanyuk, G. Yu. (2019) Nikmelnikovite, Ca12Fe2+Fe3+3Al3(SiO4)6(OH)20: A New Mineral from the Kovdor Massif (Kola Peninsula, Russia) Doklady Earth Sciences, 488 (2) 1200-1202 doi:10.1134/s1028334x19100143
Krivovichev, Sergey V.; Panikorovskii, Taras L.; Yakovenchuk, Victor N.; Selivanova, Ekaterina A.; Ivanyuk, Gregory Yu. (2021) Trigonal variation in the garnet supergroup: the crystal structure of nikmelnikovite, Ca12Fe2+Fe3+3Al3(SiO4)6(OH)20, from Kovdor massif, Kola Peninsula, Russia. Mineralogical Magazine, 85 (4). 620-626 doi:10.1180/mgm.2021.55
Localities for Nikmelnikovite
Showing 1 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.
Russia (TL) | |
| Krivovichev et al. (2019) +1 other reference |
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