Log In
Volkonskoite
A valid IMA mineral species - grandfathered
This page is currently not sponsored. Click here to sponsor this page.
About Volkonskoite
Pyotr Mikhailovich Volkonsky
Formula:
Ca0.3(Cr,Mg,Fe)2((Si,Al)4O10)(OH)2 · 4H2O
Colour:
Blue-green, dark green, grass-green
Lustre:
Waxy, Dull
Hardness:
1 - 2
Specific Gravity:
2.11 - 2.36
Crystal System:
Monoclinic
Member of:
Name:
Named in 1831 by August Alexander KĂ€mmerer in honour of Prince Pyotr Mikhailovich Volkonsky (25 April (6 May) 1776, Saint-Petersburg, Russian Empire - 27 August (8 September) 1852, Petergof, Petrodvortsovy District, Saint Petersburg, Russian Empire), Minister of the Russian Court, Russia.
Unique Identifiers
Mindat ID:
4201
Long-form identifier:
mindat:1:1:4201:3
IMA Classification of Volkonskoite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Ca0.3(Cr3+,Mg)2(Si,Al)4O10(OH)2·4H2O
First published:
1831
Classification of Volkonskoite
9.EC.40
9 : SILICATES (Germanates)
E : Phyllosilicates
C : Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets
9 : SILICATES (Germanates)
E : Phyllosilicates
C : Phyllosilicates with mica sheets, composed of tetrahedral and octahedral nets
71.3.1a.4
71 : PHYLLOSILICATES Sheets of Six-Membered Rings
3 : Sheets of 6-membered rings with 2:1 clays
71 : PHYLLOSILICATES Sheets of Six-Membered Rings
3 : Sheets of 6-membered rings with 2:1 clays
16.15.6
16 : Silicates Containing Aluminum and other Metals
15 : Aluminosilicates of V and Cr
16 : Silicates Containing Aluminum and other Metals
15 : Aluminosilicates of V and Cr
Mineral Symbols
As of 2021 there are now IMAâCNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMAâCNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMAâCNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Vkn | IMAâCNMNC | Warr, L.N. (2021). IMAâCNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Vkn | Warr (2020) | Warr, L.N. (2020) Recommended abbreviations for the names of clay minerals and associated phases. Clay Minerals, 55, 261â264 doi:10.1180/clm.2020.30 |
Physical Properties of Volkonskoite
Waxy, Dull
Transparency:
Translucent
Colour:
Blue-green, dark green, grass-green
Hardness:
1 - 2 on Mohs scale
Tenacity:
Brittle
Fracture:
Conchoidal
Density:
2.11 - 2.36 g/cm3 (Measured)
Optical Data of Volkonskoite
Type:
Biaxial (-)
RI values:
nα = 1.551 - 1.560 nβ = 1.569 nγ = 1.564
2V:
Calculated: 62° to 84°
Max. Birefringence:
δ = 0.004 - 0.013
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 ”m 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 ”m 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:
Low (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 strong
Chemistry of Volkonskoite
Mindat Formula:
Ca0.3(Cr,Mg,Fe)2((Si,Al)4O10)(OH)2 · 4H2O
Element Weights:
Common Impurities:
Ti,Mn,Na,K,C,P
Crystallography of Volkonskoite
Crystal System:
Monoclinic
Morphology:
Fine scaly to fibrous, massive.
Comment:
Point Group: n.d.; Space Group: n.d. Z = n.d
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| - Ă | () |
Comments:
No published powder X-ray diffraction data.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 3b: Earthâs earliest hydrosphere | >4.45 |
| 13 : Hadean serpentinization | |
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47e : [Vanadates, chromates, manganates] | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 53 : Other minerals with taphonomic origins | <0.4 |
Geological Setting:
Weathering product of serpentine, epigenetic mineral in clastic sedimentary rocks.
Type Occurrence of Volkonskoite
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, R4820, 16308.
Synonyms of Volkonskoite
Other Language Names for Volkonskoite
Relationship of Volkonskoite to other Species
Member of:
Other Members of Smectite Group:
| Beidellite | (Na,Ca0.5)0.3Al2((Si,Al)4O10)(OH)2 · nH2O | Mon. 2/m : B2/m |
| Ferrosaponite | Ca0.3(Fe2+,Mg,Fe3+)3((Si,Al)4O10)(OH)2 · 4H2O | Mon. |
| Hectorite | Na0.3(Mg,Li)3(Si4O10)(F,OH)2 | Mon. 2/m : B2/m |
| Montmorillonite | (Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2 · nH2O | Mon. 2/m : B2/m |
| Nontronite | Na0.3Fe2((Si,Al)4O10)(OH)2 · nH2O | Mon. 2/m : B2/m |
| 'Pimelite' | Ni3Si4O10(OH)2 · 4H2O | Hex. |
| Saliotite | (Li,Na)Al3(AlSi3O10)(OH)5 | Mon. 2/m : B2/m |
| Saponite | Ca0.25(Mg,Fe)3((Si,Al)4O10)(OH)2 · nH2O | Mon. |
| Sauconite | Na0.3Zn3((Si,Al)4O10)(OH)2 · 4H2O | Mon. |
| Stevensite | (Ca,Na)xMg3-x(Si4O10)(OH)2 | Mon. |
| Swinefordite | Li(Al,Li,Mg)3((Si,Al)4O10)2(OH,F)4 · nH2O | Mon. 2/m : B2/m |
| Yakhontovite | (Ca,Na)0.5(Cu,Fe,Mg)2(Si4O10)(OH)2 · 3H2O | Mon. |
| Zincsilite | Zn3Si4O10(OH)2 · 4H2O (?) | Mon. |
Common Associates
Associations Based on Photo Data:
| 8 photos of Volkonskoite associated with Descloizite | PbZn(VO4)(OH) |
| 5 photos of Volkonskoite associated with Melanophlogite | 46SiO2 · 6(N2,CO2) · 2(CH4,N2) |
| 4 photos of Volkonskoite associated with Quartz | SiO2 |
| 4 photos of Volkonskoite associated with Vanadinite | Pb5(VO4)3Cl |
| 3 photos of Volkonskoite associated with Baryte | BaSO4 |
| 3 photos of Volkonskoite associated with Ferrihollandite | Ba(Mn4+6Fe3+2)O16 |
| 2 photos of Volkonskoite associated with Cinnabar | HgS |
| 2 photos of Volkonskoite associated with Cerianite-(Ce) | Ce4+O2 |
| 1 photo of Volkonskoite associated with Bentorite | Ca6Cr2(SO4)3(OH)12 · 26H2O |
Related Minerals - Strunz-mindat Grouping
| 9.EC. | Meifuite | KFe6(Si7Al)O19(OH)4Cl2 |
| 9.EC. | Balestraite | KLi2V5+Si4O12 |
| 9.EC. | Voloshinite | Rb(LiAl1.5â»0.5)(Al0.5Si3.5)O10F2 |
| 9.EC.05 | Talc | Mg3Si4O10(OH)2 |
| 9.EC.05 | Minnesotaite | Fe2+3Si4O10(OH)2 |
| 9.EC.05 | Willemseite | Ni3Si4O10(OH)2 |
| 9.EC.10 | Fluorluanshiweiite | KLiAl1.5(Si3.5Al0.5)O10F2 |
| 9.EC.10 | Garmite | CsLiMg2(Si4O10)F2 |
| 9.EC.10 | Gorbunovite | CsLi2(Ti,Fe)Si4O10(F,OH,O)2 |
| 9.EC.10 | Ferripyrophyllite | Fe3+Si2O5(OH) |
| 9.EC.10 | Manganiceladonite | K(MgMn3+â»)(Si4O10)(OH)2 |
| 9.EC.10 | Luanshiweiite | KLiAl1.5(Si3.5Al0.5)O10(OH)2 |
| 9.EC.10 | Pyrophyllite | Al2Si4O10(OH)2 |
| 9.EC.15 | Paragonite | NaAl2(AlSi3O10)(OH)2 |
| 9.EC.15 | Ferroaluminoceladonite | K(Fe2+Alâ»)(Si4O10)(OH)2 |
| 9.EC.15 | Nanpingite | CsAl2(AlSi3O10)(OH,F)2 |
| 9.EC.15 | Ferroceladonite | K(Fe2+Fe3+â»)(Si4O10)(OH)2 |
| 9.EC.15 | Ganterite | Ba0.5(Na,K)0.5Al2(Si2.5Al1.5)O10(OH)2 |
| 9.EC.15 | Kreiterite | CsLi2Fe3+(Si4O10)F2 |
| 9.EC.15 | Roscoelite | KV3+2(AlSi3O10)(OH)2 |
| 9.EC.15 | Aluminoceladonite | K(MgAlâ»)(Si4O10)(OH)2 |
| 9.EC.15 | Tobelite | (NH4)Al2(AlSi3O10)(OH)2 |
| 9.EC.15 | Tainiolite | KLiMg2(Si4O10)F2 |
| 9.EC.15 | Celadonite | K(MgFe3+â»)(Si4O10)(OH)2 |
| 9.EC.15 | Chromceladonite | K(MgCrâ»)(Si4O10)(OH)2 |
| 9.EC.15 | Montdorite | KFe2+1.5Mn2+0.5Mg0.5Si4O10(F,OH)2 |
| 9.EC.15 | Chromphyllite | KCr2(AlSi3O10)(OH)2 |
| 9.EC.15 | Boromuscovite | KAl2(BSi3O10)(OH)2 |
| 9.EC.15 | 'UM1988-22-SiO:AlCaFFeHKLiMg' | KLiMgAl2Si3O10F2 |
| 9.EC.15 | Chernykhite | (Ba,Na)(V3+,Al,Mg)2((Si,Al)4O10)(OH)2 |
| 9.EC.15 | Muscovite | KAl2(AlSi3O10)(OH)2 |
| 9.EC.20 | Masutomilite | K(LiAlMn2+)[AlSi3O10]F2 |
| 9.EC.20 | Oxyphlogopite | K(Mg,Ti,Fe)3[(Si,Al)4O10](O,F)2 |
| 9.EC.20 | 'Chloroferrokinoshitalite' | (Ba,K)(Fe2+,Mg)3(Al2Si2O10)(Cl,OH,F)2 |
| 9.EC.20 | Siderophyllite | KFe2+2Al(Al2Si2O10)(OH)2 |
| 9.EC.20 | Sokolovaite | CsLi2Al(Si4O10)F2 |
| 9.EC.20 | Hendricksite | KZn3(Si3Al)O10(OH)2 |
| 9.EC.20 | Tetraferriphlogopite | KMg3(Si3Fe3+)O10(OH)2 |
| 9.EC.20 | Fluorannite | KFe2+3(Si3Al)O10F2 |
| 9.EC.20 | Aspidolite | NaMg3(AlSi3O10)(OH)2 |
| 9.EC.20 |
Efimyatskaya Mt, Efimyata Village, Chastinsky District, Perm Krai, Russia