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Dobrovolskyite
A valid IMA mineral species
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Formula:
Na4Ca(SO4)3
Lustre:
Vitreous
Hardness:
3½
Specific Gravity:
2.68 (Calculated)
Crystal System:
Trigonal
Name:
Named in honor of Prof. Dr. Vladimir Vitalievich Dolivo-Dobrovolsky (Владимир Витальевич Доливо-Добровольский) (1927–2009), St. Petersburg Mining Institute, one of the leading Russian scientists in the field of petrology, crystal optics and crystal chemistry.
Chemically and structurally related to bubnovaite. Also chemically similar to glauberite; also compare cesanite, antofagastaite, eugsterite, hydroglauberite, omongwaite, wattevillite; and 'ciempozuelite'.
Structure determined.
Structure determined.
Unique Identifiers
Mindat ID:
54346
Long-form identifier:
mindat:1:1:54346:8
IMA Classification of Dobrovolskyite
Approved
IMA Formula:
Na4Ca(S6+O4)3
First published:
2021
Type description reference:
Shablinskii, Andrey P., Filatov, Stanislav K., Krivovichev, Sergey V., Vergasova, Lidiya P., Moskaleva, Svetlana V., Avdontseva, Eugeniya Yu., Knyazev, Alexander V., Bubnova, Rimma S. (2021) Dobrovolskyite, Na4Ca(SO4)3, a new fumarolic sulfate from the Great Tolbachik fissure eruption, Kamchatka Peninsula, Russia. Mineralogical Magazine, 85 (2) 233-241 doi:10.1180/mgm.2021.9
Classification of Dobrovolskyite
7.AD.
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
A : Sulfates (selenates, etc.) without additional anions, without H2O
D : With only large cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
A : Sulfates (selenates, etc.) without additional anions, without H2O
D : With only large cations
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 |
|---|---|---|
| Dvo | 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 Dobrovolskyite
Vitreous
Streak:
White
Hardness:
3½ on Mohs scale
Parting:
None observed
Fracture:
Conchoidal
Density:
2.68 g/cm3 (Calculated)
Comment:
Calculated based on empirical formula and single crystal unit-cell parameters
Optical Data of Dobrovolskyite
Type:
Uniaxial (+)
RI values:
nω = 1.489(2) nε = 1.491(2)
Max. Birefringence:
δ = 0.002
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:
Moderate (negative)
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.
Dispersion:
None observed
Pleochroism:
Not Visible
Chemistry of Dobrovolskyite
Mindat Formula:
Na4Ca(SO4)3
Element Weights:
Elements listed:
Crystallography of Dobrovolskyite
Crystal System:
Trigonal
Class (H-M):
3 - Pyramidal
Space Group:
R3
Cell Parameters:
a = 15.7223(2) Å, c = 22.0160(5) Å
Ratio:
a:c = 1 : 1.4
Unit Cell V:
4713.1 ų
Z:
18
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 11.58 Å | (40) |
| 5.79 Å | (22) |
| 3.86 Å | (88) |
| 3.67 Å | (32) |
| 3.11 Å | (24) |
| 3.09 Å | (26) |
| 2.855 Å | (50) |
| 2.682 Å | (100) |
Reference:
Shablinskii, Andrey P., Filatov, Stanislav K., Krivovichev, Sergey V., Vergasova, Lidiya P., Moskaleva, Svetlana V., Avdontseva, Eugeniya Yu., Knyazev, Alexander V., Bubnova, Rimma S. (2021) Dobrovolskyite, Na4Ca(SO4)3, a new fumarolic sulfate from the Great Tolbachik fissure eruption, Kamchatka Peninsula, Russia. Mineralogical Magazine, 85 (2) 233-241 doi:10.1180/mgm.2021.9
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 45a : [Sulfates, arsenates, selenates, antimonates] |
Type Occurrence of Dobrovolskyite
General Appearance of Type Material:
Aggregates of tabular crystals up to 1-2 mm in maximum dimension, with abundant gas inclusions.
Place of Conservation of Type Material:
Collections of the Saint Petersburg State University mineralogical museum, University Emb. 7/9, St. Petersburg 199034, Russia, catalogue number 1/19829
Geological Setting of Type Material:
Fumarole, about 200°C
Associated Minerals at Type Locality:
Reference:
Shablinskii, Andrey P., Filatov, Stanislav K., Krivovichev, Sergey V., Vergasova, Lidiya P., Moskaleva, Svetlana V., Avdontseva, Eugeniya Yu., Knyazev, Alexander V., Bubnova, Rimma S. (2021) Dobrovolskyite, Na4Ca(SO4)3, a new fumarolic sulfate from the Great Tolbachik fissure eruption, Kamchatka Peninsula, Russia. Mineralogical Magazine, 85 (2) 233-241 doi:10.1180/mgm.2021.9
Other Language Names for Dobrovolskyite
Related Minerals - Strunz-mindat Grouping
| 7.AD. | Bubnovaite | K2Na8Ca(SO4)6 |
| 7.AD. | Calciolangbeinite | K2Ca2(SO4)3 |
| 7.AD. | Murphyite | Pb(Te6+O4) |
| 7.AD. | Cuprodobrovolskyite | Na4Cu(SO4)3 |
| 7.AD. | Kristjánite | KNa2H(SO4)2 |
| 7.AD.05 | Mascagnite | (NH4)2SO4 |
| 7.AD.05 | Arcanite | K2SO4 |
| 7.AD.10 | Mercallite | KHSO4 |
| 7.AD.15 | Misenite | K8H6(SO4)7 |
| 7.AD.20 | Letovicite | (NH4)3H(SO4)2 |
| 7.AD.25 | Thénardite | Na2SO4 |
| 7.AD.25 | Glauberite | Na2Ca(SO4)2 |
| 7.AD.30 | Metathénardite | Na2SO4 |
| 7.AD.30 | Anhydrite | CaSO4 |
| 7.AD.35 | Baryte | BaSO4 |
| 7.AD.35 | Celestine | SrSO4 |
| 7.AD.35 | Olsacherite | Pb2(Se6+O4)(SO4) |
| 7.AD.35 | Anglesite | PbSO4 |
| 7.AD.40 |