Gerasimovskite
A valid IMA mineral species - grandfathered
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About Gerasimovskite
Gerasimovsky, Vasily Ivanovich
Formula:
Mn2+(Nb,Ti)5O12 · 9H2O (?)
Colour:
brown to gray or light gray
Lustre:
Pearly
Hardness:
2
Specific Gravity:
2.52 - 2.58
Crystal System:
Amorphous
Name:
Named in 1957 by Evgeny Ivanovich Semenov in honor of Vasilii Ivanovich Gerasimovsky (Василий Иванович Герасимовский) (20 June 1907, village of Artemyevskaya, Vologda province - 11 August 1979, Transbaikalia) in 1934, discovered (together with O.A. Vorobyova) industrial deposits of loparite ore on the Kola Peninsula.
This page provides mineralogical data about Gerasimovskite.
Unique Identifiers
Mindat ID:
1678
Long-form identifier:
mindat:1:1:1678:6
IMA Classification of Gerasimovskite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Mn2+Ti4+3Nb5+2O12·9H2O
First published:
1957
Classification of Gerasimovskite
4.FM.25
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
M : Hydroxides with H2O +- (OH); unclassified
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
F : Hydroxides (without V or U)
M : Hydroxides with H2O +- (OH); unclassified
8.7.8.3
8 : MULTIPLE OXIDES CONTAINING NIOBIUM,TANTALUM OR TITANIUM
7 : Miscellaneous
8 : MULTIPLE OXIDES CONTAINING NIOBIUM,TANTALUM OR TITANIUM
7 : Miscellaneous
18.1.37
18 : Niobates and Tantalates
1 : Niobates and tantalates containing neither rare earths nor U
18 : Niobates and Tantalates
1 : Niobates and tantalates containing neither rare earths nor U
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 |
|---|---|---|
| Gms | 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 Gerasimovskite
Pearly
Colour:
Brown to gray or light gray
Hardness:
2 on Mohs scale
Cleavage:
Perfect
In one direction
In one direction
Density:
2.52 - 2.58 g/cm3 (Measured)
Optical Data of Gerasimovskite
Type:
Biaxial (-)
RI values:
nα = 1.74 nβ = 1.81 nγ = 1.81
2V:
Measured: 18°
Max. Birefringence:
δ = 0.070
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 moderate
Optical Extinction:
Parallel extinction, elongation positive.
Chemistry of Gerasimovskite
Mindat Formula:
Mn2+(Nb,Ti)5O12 · 9H2O (?)
Crystallography of Gerasimovskite
Crystal System:
Amorphous
Comment:
diffuse lines at 2.60, 1.85, and 1.64 A.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 1.89 Å | (100) |
| 3.70 Å | (80) |
| 3.18 Å | (60) |
| 2.10 Å | (40) |
| 1.64 Å | (20) |
Comments:
Lovozero massif, Russia. Data collected after heating the sample at 900°C.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks |
Type Occurrence of Gerasimovskite
General Appearance of Type Material:
Platy masses up to 1.5x1x0.3 cm.
Geological Setting of Type Material:
In ussingite-bearing pegmatites. Thought to have formed by the hydrothermal alteration of minerals of the murmanite-lomonosovite series.
Synonyms of Gerasimovskite
Other Language Names for Gerasimovskite
Dutch:Gerasimovskiet
German:Gerasimovskit
Gerassimovskit
Gerassimovskit
Russian:Герасимовскит
Spanish:Gerasimovskita
Gerassimovskita
Gerassimovskita
Relationship of Gerasimovskite to other Species
Forms a series with:
Common Associates
Associations Based on Photo Data:
| 3 photos of Gerasimovskite associated with Aegirine | NaFe3+Si2O6 |
| 3 photos of Gerasimovskite associated with Ussingite | Na2AlSi3O8OH |
| 2 photos of Gerasimovskite associated with Birnessite | (Na,Ca)0.5(Mn4+,Mn3+)2O4 · 1.5H2O |
| 1 photo of Gerasimovskite associated with Manganonordite-(Ce) | Na3SrCeMn2+Si6O17 |
| 1 photo of Gerasimovskite associated with Albite | Na(AlSi3O8) |
| 1 photo of Gerasimovskite associated with Pectolite | NaCa2Si3O8(OH) |
Related Minerals - Strunz-mindat Grouping
| 4.FM. | Charleshatchettite | CaNb4O10(OH)2 · 8H2O |
| 4.FM.15 | Franconite | Na(Nb2O5)(OH) · 3H2O |
| 4.FM.15 | Hochelagaite | (Ca,Na,Sr)(Nb,Ti,Si,Al)4O11 · 8H2O |
| 4.FM.15 | Ternovite | (Mg,Ca)Nb4O11 · nH2O |
| 4.FM.25 | Belyankinite | Ca1-2(Ti,Zr,Nb)5O12 · 9H2O (?) |
| 4.FM.25 | Manganbelyankinite | Mn2+(Ti,Nb)5O12 · 9H2O |
| 4.FM.30 | Silhydrite | Si3O6 · H2O |
| 4.FM.35 | Cuzticite | Fe3+2(TeO6) · 3H2O |
| 4.FM.50 | Qatranaite | CaZn2(OH)6(H2O)2 |
| 4.FM.55 | 'Hydroplumbite' | 3PbO · H2O |
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 Gerasimovskite
mindat.org URL:
https://www.mindat.org/min-1678.html
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Please feel free to link to this page.
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References for Gerasimovskite
Reference List:
Localities for Gerasimovskite
Showing 11 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.
Greenland | |
| Petersen et al. (1993) +1 other reference |
Russia | |
| ... |
| Pekov (1998) |
| Pekov (2000) |
| Arzamastsev et al. (2008) | |
| Pekov (2000) | |
| Pekov (1998) |
| Trud.Inst.min.geokh.cryst. redkikh elementov (1957) +3 other references | |
| Pekov et al. (2013) | |
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Lovozero Massif, Murmansk Oblast, Russia