Ilmajokite-(Ce)
A valid IMA mineral species
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About Ilmajokite-(Ce)
Formula:
Na11KBaCe2Ti12Si37.5O94(OH)31 · 29H2O
formerly given as (Na,Ce,Ba)2TiSi3O5(OH)10.nH2O and (Na,Ce,Ba)10Ti5Si14O22(OH)44.nH2O
Colour:
Bright yellow
Lustre:
Vitreous
Hardness:
1
Crystal System:
Monoclinic
Name:
Named for the Ilmajok River, Russia, located near the type locality. It was originally named simply ilmajokite and renamed in 2020 after new data showed a REE as a species-forming element. The new name follows the IMA nomenclature (Levinson rule) for REEs.
The crystal structure is based upon complex porous titanosilicate framework in which the SiO4 tetrahedra form a three-dimensional structure with a previously unknown topology.
Third (?) most structurally complex mineral after ewingite and morrisonite (also compare batoniite).
Structural complexity: 8.468 bits per atom; 11990.129 bits per cell.
The most complex mineral framework structure (complexity comparable to that of paulingite-Ca).
Compare heamanite-(Ce), that, however, is not a silicate but an oxide.
Third (?) most structurally complex mineral after ewingite and morrisonite (also compare batoniite).
Structural complexity: 8.468 bits per atom; 11990.129 bits per cell.
The most complex mineral framework structure (complexity comparable to that of paulingite-Ca).
Compare heamanite-(Ce), that, however, is not a silicate but an oxide.
Unique Identifiers
Mindat ID:
2012
Long-form identifier:
mindat:1:1:2012:7
IMA Classification of Ilmajokite-(Ce)
Approved
IMA status notes:
Redefined by the IMA, Renamed by the IMA
IMA Formula:
Na11KBaCe3+2Ti4+12Si37.5O94(OH)30(H2O)24·5H2O
Approval year:
1971
First published:
1972
Approval history:
Approved as IMA1971-027, as Ilmajokite.
2019: Revised chemical formula as Na11KBaCe2Ti12Si37.5O94(OH)31·29H2O and renamed as Ilmajokite-(Ce). (CNMNC Newsletter 53)
2019: Revised chemical formula as Na11KBaCe2Ti12Si37.5O94(OH)31·29H2O and renamed as Ilmajokite-(Ce). (CNMNC Newsletter 53)
Classification of Ilmajokite-(Ce)
9.HB.05
9 : SILICATES (Germanates)
H : Unclassified silicates
B : With Ti, V, Cr
9 : SILICATES (Germanates)
H : Unclassified silicates
B : With Ti, V, Cr
78.7.5.1
78 : Unclassified Silicates
7 :
78 : Unclassified Silicates
7 :
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 |
|---|---|---|
| Ijk-Ce | 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 Ilmajokite-(Ce)
Vitreous
Transparency:
Transparent, Translucent
Colour:
Bright yellow
Hardness:
1 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
Optical Data of Ilmajokite-(Ce)
Type:
Biaxial (+)
RI values:
nα = 1.573 nβ = 1.576 nγ = 1.579
2V:
Measured: 90° , Calculated: 88°
Max. Birefringence:
δ = 0.006
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 (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 Ilmajokite-(Ce)
Mindat Formula:
Na11KBaCe2Ti12Si37.5O94(OH)31 · 29H2O
formerly given as (Na,Ce,Ba)2TiSi3O5(OH)10.nH2O and (Na,Ce,Ba)10Ti5Si14O22(OH)44.nH2O
formerly given as (Na,Ce,Ba)2TiSi3O5(OH)10.nH2O and (Na,Ce,Ba)10Ti5Si14O22(OH)44.nH2O
Element Weights:
Common Impurities:
Zr,Al,TR,Fe,Nb,Ta,Ca,Sr,K,C
Crystallography of Ilmajokite-(Ce)
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/b
Setting:
C2/c
Cell Parameters:
a = 35.908(5) Å, b = 27.784(3) Å, c = 33.126(4) Å
β = 96.494(3)°
β = 96.494(3)°
Ratio:
a:b:c = 1.292 : 1 : 1.192
Unit Cell V:
32,836.70 ų (Calculated from Unit Cell)
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 11.5 Å | (100) |
| 10.9 Å | (70) |
| 10.2 Å | (90) |
| 4.3 Å | (100) |
| 3.7 Å | (70) |
| 3.1 Å | (90) |
| 2.44 Å | (100) |
Comments:
Lovozero massif, Russia. The data are from the type description.
Type Occurrence of Ilmajokite-(Ce)
General Appearance of Type Material:
Granular deposits, crusts, and brushes of crystals.
Place of Conservation of Type Material:
Geology Museum, Kola Branch, Academy of Sciences, Russia, 3152, 3153.
Mining Institute, St. Petersburg, Russia, 1061/1-2.
A.E. Fersman Mineralogical Museum, Academy of Sciences, Moscow, Russia, 74041, 74080, 74490, 74491.
National School of Mines, Paris, France.
Mining Institute, St. Petersburg, Russia, 1061/1-2.
A.E. Fersman Mineralogical Museum, Academy of Sciences, Moscow, Russia, 74041, 74080, 74490, 74491.
National School of Mines, Paris, France.
Geological Setting of Type Material:
Alkaline pegmatite.
Synonyms of Ilmajokite-(Ce)
Other Language Names for Ilmajokite-(Ce)
Common Associates
Associations Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 9.HB. | Waipouaite | Ca3V4+5O9[Si2O5(OH)2][Si3O7(OH)2] · 11H2O |
| 9.HB.10 | Rilandite | Cr6SiO11 · 5H2O (?) |
Radioactivity
Other Information
Notes:
Decomposes in water at 20°C, giving amorphous silica and in acid, giving slight effervescence and amorphous silica gel.
Special Storage/
Display Requirements:
Display Requirements:
Unstable in ambient conditions.
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 Ilmajokite-(Ce)
mindat.org URL:
https://www.mindat.org/min-2012.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Ilmajokite-(Ce)
Reference List:
Zolotarev, Andrey A., Krivovichev, Sergey V., Cámara, Fernando, Bindi, Luca, Zhitova, Elena S., Hawthorne, Frank, Sokolova, Elena (2020) Extraordinary structural complexity of ilmajokite: a multilevel hierarchical framework structure of natural origin. IUCrJ, 7 (1). 121-128 doi:10.1107/s2052252519016622
Localities for Ilmajokite-(Ce)
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) | |
| Bussen et al. (1972) +3 other references |
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Yubileinaya pegmatite, Karnasurt Mountain, Lovozersky District, Murmansk Oblast, Russia