Vyacheslavite
A valid IMA mineral species
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About Vyacheslavite
Vyacheslav Gavrilovich Melkov
Formula:
U(PO4)(OH)
Based on new structure data obtained on natural material it is not likely that vyacheslavite contains molecular water (Steciuk et al., 2019).
Colour:
Green to dark green
Lustre:
Greasy
Crystal System:
Orthorhombic
Name:
Named after Vyacheslav Gavrilovich Melkov (Вячеслав Гаврилович Мелков) (1911-1991), Russian mineralogist specializing in uranium minerals. Another mineral, melkovite, was also named after him.
This page provides mineralogical data about Vyacheslavite.
Unique Identifiers
Mindat ID:
4218
Long-form identifier:
mindat:1:1:4218:1
IMA Classification of Vyacheslavite
Approved
IMA Formula:
U4+(PO4)(OH)
Approval year:
1983
First published:
1984
Classification of Vyacheslavite
8.DN.20
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
N : With only large cations
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
N : With only large cations
40.4.8.3
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
4 : (AB)5(XO4)2·xH2O
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
4 : (AB)5(XO4)2·xH2O
19.11.5
19 : Phosphates
11 : Phosphates of U
19 : Phosphates
11 : Phosphates of 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 |
|---|---|---|
| Vya | 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 Vyacheslavite
Optical Data of Vyacheslavite
Type:
Biaxial (-)
RI values:
nα = 1.700 nβ = 1.726 - 1.729 nγ = 1.729 - 1.731
2V:
Measured: Small°
Max. Birefringence:
δ = 0.029 - 0.031
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.
No measured or calculated 2V is on file for this mineral, so the value used here (33°) 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 (33°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
r > v strong
Pleochroism:
Weak
Comments:
In shades of green.
Comments:
Positive elongation.
Chemistry of Vyacheslavite
Mindat Formula:
U(PO4)(OH)
Based on new structure data obtained on natural material it is not likely that vyacheslavite contains molecular water (Steciuk et al., 2019).
Based on new structure data obtained on natural material it is not likely that vyacheslavite contains molecular water (Steciuk et al., 2019).
Element Weights:
Elements listed:
Crystallography of Vyacheslavite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Cmca
Cell Parameters:
a = 6.96 Å, b = 9.07 Å, c = 12.27 Å
Ratio:
a:b:c = 0.767 : 1 : 1.353
Unit Cell V:
775 ų
Z:
8
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.19 Å | (100) |
| 2.69 Å | (70) |
| 4.56 Å | (60) |
| 4.13 Å | (60) |
| 3.68 Å | (50) |
| 2.71 Å | (50) |
| 3.04 Å | (30) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] |
Type Occurrence of Vyacheslavite
Co-Type Localities:
General Appearance of Type Material:
Green to dark green tabular crystals and aggregates on quartz. Crystals are up to 8 μm long and 1.5 μm wide.
Place of Conservation of Type Material:
Mining Institute, St. Petersburg, Russia, 1692/1.
A.E. Fersman Mineralogical Museum, Academy of Sciences, Moscow, Russia, 82773.
A.E. Fersman Mineralogical Museum, Academy of Sciences, Moscow, Russia, 82773.
Geological Setting of Type Material:
Secondary mineral in a uranium deposit.
Associated Minerals at Type Locality:
Synonyms of Vyacheslavite
Other Language Names for Vyacheslavite
Common Associates
Associations Based on Photo Data:
| 1 photo of Vyacheslavite associated with 'Stink-Fluss' | CaF2 |
Related Minerals - Strunz-mindat Grouping
| 8.DN. | Loomisite | Ba[Be2P2O8] · H2O |
| 8.DN.05 | Natrophosphate | Na6+xHxF(PO4)2 · (19+x)H2O |
| 8.DN.10 | Isoclasite | Ca2(PO4)(OH) · 2H2O |
| 8.DN.15 | 'Urphoite' | U4+6(PO4)7(OH)3 · 4H2O |
| 8.DN.15 | Lermontovite | U(PO4)(OH) · H2O |
Radioactivity
Other Information
Notes:
Radioactive.
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 Vyacheslavite
mindat.org URL:
https://www.mindat.org/min-4218.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
Mineral Dealers:
References for Vyacheslavite
Reference List:
Dunn, Pete J., Fleischer, Michael, Langley, Richard H., Shigley, James E., Zilczer, Janet A. (1985) New mineral names. American Mineralogist, 70 (7-8) 871-881 p.878
Localities for Vyacheslavite
Showing 10 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.
Czech Republic | |
| Pauliš P. et al. (Kutna Hora, issue 1) |
| Pauliš P. et al. (Kutna Hora, issue 1) | |
| Scharm (1995) | |
Germany | |
| 50. (in German) +1 other reference |
| Walenta (1996) |
| Dill et al. (2008) |
Poland | |
| Twardak et al. (2018) |
Slovakia | |
| Koděra |
Uzbekistan (TL) | |
| Belova et al. (1984) +1 other reference |
| Belova et al. (1984) +1 other reference |
Quick NavTopAbout VyacheslaviteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatRadioactivityOther InformationInternet Links References Localities Locality List
Krunkelbach Valley Uranium deposit, Menzenschwand, St Blasien, Waldshut, Freiburg Region, Baden-Württemberg, Germany