Čejkaite
A valid IMA mineral species
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About Čejkaite
Jiří Čejka
Formula:
Na4(UO2)(CO3)3
Colour:
pale yellow to beige
Lustre:
Vitreous
Specific Gravity:
3.67
Crystal System:
Monoclinic
Name:
In honour of Dr. Jiří Čejka (born September 2, 1929, deceased September 2, 2025), the Czech chemist and spectroscopist, who contributed mainly to the spectroscopy and thermal analysis of uranium minerals. Jiří served as a director of the Natural History Museum of the National Museum, Prague, Czech Republic, until 2001. He had earlier published a study on the thermal decomposition of the synthetic analog of the mineral later named in his honor.
This page provides mineralogical data about Čejkaite.
Name Encoding
CP1252:
Cejkaite
Latin-1:
Cejkaite
ASCII-7:
Cejkaite
Unique Identifiers
Mindat ID:
7105
Long-form identifier:
mindat:1:1:7105:1
IMA Classification of Čejkaite
Approved
IMA Formula:
Na4U6+O2(CO3)3
Approval year:
1999
First published:
2003
Approval history:
IMA1999-045
Classification of Čejkaite
5.ED.50
5 : CARBONATES (NITRATES)
E : Uranyl Carbonates
D : UO2:CO3 = 1:3
5 : CARBONATES (NITRATES)
E : Uranyl Carbonates
D : UO2:CO3 = 1:3
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 |
|---|---|---|
| Čej | 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 Čejkaite
Vitreous
Colour:
Pale yellow to beige
Streak:
Light yellow
Density:
3.67 g/cm3 (Measured) 3.74 g/cm3 (Calculated)
Comment:
Calculated density from Plášil et al. (2013).
Chemistry of Čejkaite
Mindat Formula:
Na4(UO2)(CO3)3
Element Weights:
Elements listed:
Crystallography of Čejkaite
Crystal System:
Monoclinic
Class (H-M):
m - Domatic
Space Group:
Bb
Setting:
Cc
Cell Parameters:
a = 9.2919(8) Å, b = 16.0991(11) Å, c = 6.4436(3) Å
α = 90°, β = 91.404(5)°, γ = 90°
α = 90°, β = 91.404(5)°, γ = 90°
Ratio:
a:b:c = 0.577 : 1 : 0.4
Unit Cell V:
963.62 ų
Z:
4
Comment:
Cell data from Plášil et al. (2013).
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.058 Å | (42) |
| 5.084 Å | (31) |
| 5.029 Å | (41) |
| 4.971 Å | (47) |
| 4.647 Å | (100) |
| 3.220 Å | (35) |
| 2.6839 Å | (43) |
| 2.3241 Å | (30) |
| 1.7565 Å | (39) |
Comments:
From Plášil et al. (2013).
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47c : [Carbonates, phosphates, borates, nitrates] | |
| 47f : [Uranyl (U⁶⁺) minerals] | |
| 47h : [Near-surface oxidized, dehydrated minerals] |
Type Occurrence of Čejkaite
General Appearance of Type Material:
Thin earthy efflorescence. Crystals range from 0.2 to 0.6 um.
Place of Conservation of Type Material:
National Museum, Prague, Czech Republic (P1p 17/99).
Geological Setting of Type Material:
Secondary mineral in a uranium deposit. Forms at pH > 6.5.
Associated Minerals at Type Locality:
Synonyms of Čejkaite
Other Language Names for Čejkaite
Common Associates
Associations Based on Photo Data:
| 10 photos of Čejkaite associated with Grimselite | K3Na(UO2)(CO3)3 · H2O |
| 5 photos of Čejkaite associated with Andersonite | Na2Ca(UO2)(CO3)3 · 5.33H2O |
| 3 photos of Čejkaite associated with Apexite | NaMg(PO4) · 9H2O |
| 2 photos of Čejkaite associated with Línekite | K2Ca3[(UO2)(CO3)3]2 · 8H2O |
| 2 photos of Čejkaite associated with Malachite | Cu2(CO3)(OH)2 |
| 1 photo of Čejkaite associated with Calcite | CaCO3 |
| 1 photo of Čejkaite associated with Quartz | SiO2 |
Related Minerals - Strunz-mindat Grouping
| 5.ED. | Szilagyiite | NaCa3(UO2)(CO3)3(SeO3)F(H2O)6 |
| 5.ED. | Pendevilleite-(Y) | Mg2Y3Al(UO2)2(CO3)7(OH)6(H2O)16 |
| 5.ED. | Paramarkeyite | Ca2(UO2)(CO3)3 · 5H2O |
| 5.ED.05 | Bayleyite | Mg2(UO2)(CO3)3 · 18H2O |
| 5.ED.10 | Swartzite | MgCa(UO2)(CO3)3 · 12H2O |
| 5.ED.15 | Albrechtschraufite | Ca4Mg(UO2)2(CO3)6F2 · 17-18H2O |
| 5.ED.20 | Liebigite | Ca2(UO2)(CO3)3 · 11H2O |
| 5.ED.25 | Rabbittite | Ca3Mg3(UO2)2(CO3)6(OH)4 · 18H2O |
| 5.ED.30 | Andersonite | Na2Ca(UO2)(CO3)3 · 5.33H2O |
| 5.ED.35 | Grimselite | K3Na(UO2)(CO3)3 · H2O |
| 5.ED.40 | Widenmannite | Pb2(OH)2[(UO2)(CO3)2] |
| 5.ED.45 | Znucalite | Zn10Ca0.83(UO2)0.83(CO3)4(OH)15.31(H2O)5.48 |
| 5.ED.50 | Agricolaite | K4(UO2)(CO3)3 |
| 5.ED.55 | Línekite | K2Ca3[(UO2)(CO3)3]2 · 8H2O |
| 5.ED.55 | Braunerite | K2Ca(UO2)(CO3)3 · 6H2O |
| 5.ED.60 | Leószilárdite | Na6Mg(UO2)2(CO3)6 · 6H2O |
| 5.ED.65 | Pseudomarkeyite | Ca8(UO2)4(CO3)12 · 21H2O |
| 5.ED.65 | Natromarkeyite | Na2Ca8(UO2)4(CO3)13 · 27H2O |
| 5.ED.65 | Markeyite | Ca9(UO2)4(CO3)13 · 28H2O |
| 5.ED.70 | Paddlewheelite | MgCa5Cu2(UO2)4(CO3)12(H2O)33 |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 43.9157% | 10,978,925 | α, β, γ |
| Thorium (Th) | 0.0000% | 0 | α, β, γ |
| Potassium (K) | 0.0000% | 0 | β, γ |
For comparison:
- Banana: ~15 Bq per fruit
- Granite: 1,000–3,000 Bq/kg
- EU exemption limit: 10,000 Bq/kg
Note: Risk is shown relative to daily recommended maximum exposure to non-background radiation of 1000 µSv/year. Note that natural background radiation averages around 2400 µSv/year so in reality these risks are probably extremely overstated! With infrequent handling and safe storage natural radioactive minerals do not usually pose much risk.
Interactive Simulator:
Note: The mass selector refers to the mass of radioactive mineral present, not the full specimen, also be aware that the matrix may also be radioactive, possibly more radioactive than this mineral!
Activity: –
| Distance | Dose rate | Risk |
|---|---|---|
| 1 cm | ||
| 10 cm | ||
| 1 m |
The external dose rate (D) from a radioactive mineral is estimated by summing the gamma radiation contributions from its Uranium, Thorium, and Potassium content, disregarding daughter-product which may have a significant effect in some cases (eg 'pitchblende'). This involves multiplying the activity (A, in Bq) of each element by its specific gamma ray constant (Γ), which accounts for its unique gamma emissions. The total unshielded dose at 1 cm is then scaled by the square of the distance (r, in cm) and multiplied by a shielding factor (μshield). This calculation provides a 'worst-case' or 'maximum risk' estimate because it assumes the sample is a point source and entirely neglects any self-shielding where radiation is absorbed within the mineral itself, meaning actual doses will typically be lower. The resulting dose rate (D) is expressed in microsieverts per hour (μSv/h).
D = ((AU × ΓU) + (ATh × ΓTh) + (AK × ΓK)) / r2 × μshield
Fluorescence of Čejkaite
Weak yellow to yellow-green in SW and LW UV.
Other Information
Notes:
Readily soluble with effervescence in diluted acids and even soluble in water with pH < 6.5.
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 Čejkaite
mindat.org URL:
https://www.mindat.org/min-7105.html
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References for Čejkaite
Reference List:
Li, Yaping, Krivovichev, S. V., Burns, P. C. (2001) The crystal structure of Na4(UO2)(CO3)3 and its relationship to schröckingerite. Mineralogical Magazine, 65 (2) 297-304 doi:10.1180/002646101550262
Císařová, Ivana; Skála, Roman; Ondruš, Petr; Drábek, Milan (2001) Trigonal Na4[UO2(CO3)3]. Acta Crystallographica Section E Structure Reports Online, 57 (5). p.i32-i34. doi:10.1107/s1600536801005992
Ondruš, Petr, Skála, Roman, Veselovský, Františsek, Sejkora, Jiří, Vitti, Cecilia (2003) Čejkaite, the triclinic polymorph of Na4(UO2)(CO3)3—a new mineral from Jáchymov, Czech Republic. American Mineralogist, 88 (4) 686-693 doi:10.2138/am-2003-0422
Burns, Peter C. (2005) U6+ minerals and inorganic compounds: insights into an expanded structural hierarchy of crystal structures. The Canadian Mineralogist, 43 (6) 1839-1894 doi:10.2113/gscanmin.43.6.1839
Čejka, Jiří, Sejkora, Jiří, Plášil, Jakub, Bahfenne, Silmarilly, Palmer, Sara J., Frost, Ray L. (2009) Raman spectroscopic study of the uranyl carbonate mineral čejkaite and its comparison with synthetic trigonal Na4[UO2(CO3)3]. Journal of Raman Spectroscopy, 41 (4) 459-464 doi:10.1002/jrs.2349
Plášil, J., Fejfarová, K., Dušek, M., Škoda, R., Rohlíček, J. (2013) Actinides in Geology, Energy, and the Environment: Revision of the symmetry and the crystal structure of cejkaite, Na4(UO2)(CO3)3. American Mineralogist, 98 (4) 549-553 doi:10.2138/am.2013.4331
Localities for Čejkaite
Showing 14 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 | |
| Jambor et al. (1999) |
| Tvrdý et al. (2010) | |
| Plášil et al. (2013) | |
| Excalibur Mineral Company specimen | |
| Ondruš et al. (2003) |
| Collection of Alex Earl |
| Bull. mineral.-petrolog. Odd. Nár. Muz. (Praha) |
| Sejkora et al. (2008) +1 other reference | |
Hungary | |
| Szakáll |
Spain | |
| Eureka blogspot +1 other reference |
Ukraine | |
| Burakov et al. () +1 other reference |
USA | |
| Excalibur Mineral Corp. - Mineral News +1 other reference |
| Caldwell (2018) |
| Travis Olds collection +1 other reference |
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Svornost Mine, Jáchymov, Karlovy Vary District, Karlovy Vary Region, Czech Republic