Schröckingerite
A valid IMA mineral species - grandfathered
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About Schröckingerite
Baron Julius Schröckinger von Neudenberg
Formula:
NaCa3(UO2)(CO3)3(SO4)F · 10H2O
Colour:
Greenish yellow
Lustre:
Sub-Vitreous, Pearly
Hardness:
2½
Specific Gravity:
2.51
Crystal System:
Triclinic
Name:
Named in 1873 by Albrecht Schrauf in honour of Baron Julius von Schröckinger (January 13, 1813, Brno, Czech Republic – December 1, 1882, Vienna, Austria) who found, and later described, the mineral as an alteration product of uraninite. Also known as Julius von Schröckinger von Neudenberg and Julius Freiherr von Schröckinger, he was a noted naturalist with particular strengths in mineralogy and malacology, and was an Austrian government official who attained the rank of Head of the Ministry of Agriculture.
Name Encoding
ASCII-7:
Schrockingerite
Unique Identifiers
Mindat ID:
3584
Long-form identifier:
mindat:1:1:3584:8
IMA Classification of Schröckingerite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
NaCa3(U6+O2)(S6+O4)(CO3)3F·10H2O
First published:
1873
Classification of Schröckingerite
5.EG.05
5 : CARBONATES (NITRATES)
E : Uranyl Carbonates
G : With SO4 or SiO4
5 : CARBONATES (NITRATES)
E : Uranyl Carbonates
G : With SO4 or SiO4
17.1.5.1
17 : COMPOUND CARBONATES
1 : Miscellaneous
17 : COMPOUND CARBONATES
1 : Miscellaneous
12.2.18
12 : Carbonates with other anions
2 : Carbonates with sulphate
12 : Carbonates with other anions
2 : Carbonates with sulphate
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 |
|---|---|---|
| Srö | 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 Schröckingerite
Sub-Vitreous, Pearly
Transparency:
Transparent
Colour:
Greenish yellow
Hardness:
2½ on Mohs scale
Cleavage:
Perfect
On {0001}.
On {0001}.
Density:
2.51 g/cm3 (Measured)
Optical Data of Schröckingerite
Type:
Biaxial (-)
RI values:
nα = 1.495 nβ = 1.543 nγ = 1.544
Max. Birefringence:
δ = 0.049
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:
None to Very Low
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 (16°) 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 (16°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
weak
Optical Extinction:
X ~ c; Y ~ b; Z ~ a.
Pleochroism:
Visible
Comments:
X = colorless, pale yellow; Y = Z = greenish yellow.
Chemistry of Schröckingerite
Mindat Formula:
NaCa3(UO2)(CO3)3(SO4)F · 10H2O
Element Weights:
Crystallography of Schröckingerite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 9.634(1) Å, b = 9.635(1) Å, c = 14.391(2) Å
α = 91.41(1)°, β = 92.33(1)°, γ = 120.26(1)°
α = 91.41(1)°, β = 92.33(1)°, γ = 120.26(1)°
Ratio:
a:b:c = 1 : 1 : 1.494
Unit Cell V:
1,151.29 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Scaly crystals flattened on {0001}, sometimes with a six-sided outline and interfacial angles of about 60°, as clusters or spherical aggregates.
Comment:
Pseudohexagonal.
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| M12056 | Schröckingerite | Mereiter, K. (1986) Crystal structure and crystallographic properties of a schröckingerite from Joachimsthal. Tschermaks mineralogische und petrographische Mitteilungen, 35(1), 1-18. | 1986 | Jáchymov, Karlovy Vary District, Karlovy Vary Region, Czech Republic | 0 | 0 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 14.28 Å | (30) |
| 8.48 Å | (70) |
| 7.26 Å | (100) |
| 5.421 Å | (20) |
| 4.796 Å | (80) |
| 4.167 Å | (20) |
| 2.876 Å | (70) |
Comments:
Synthetic.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47b : [Sulfates and sulfites] | |
| 47c : [Carbonates, phosphates, borates, nitrates] | |
| 47f : [Uranyl (U⁶⁺) minerals] | |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 55 : Anthropogenic mine minerals |
Type Occurrence of Schröckingerite
Place of Conservation of Type Material:
Natural History Museum, Vienna, Austria, A.a.6740.
Synonyms of Schröckingerite
Other Language Names for Schröckingerite
Common Associates
Associations Based on Photo Data:
| 19 photos of Schröckingerite associated with Andersonite | Na2Ca(UO2)(CO3)3 · 5.33H2O |
| 13 photos of Schröckingerite associated with Rabbittite | Ca3Mg3(UO2)2(CO3)6(OH)4 · 18H2O |
| 7 photos of Schröckingerite associated with Bayleyite | Mg2(UO2)(CO3)3 · 18H2O |
| 7 photos of Schröckingerite associated with 'Sandstone' | |
| 6 photos of Schröckingerite associated with Quartz | SiO2 |
| 4 photos of Schröckingerite associated with Metamunirite | NaVO3 |
| 4 photos of Schröckingerite associated with Uraninite | UO2 |
| 3 photos of Schröckingerite associated with Liebigite | Ca2(UO2)(CO3)3 · 11H2O |
| 3 photos of Schröckingerite associated with Zellerite | Ca(UO2)(CO3)2 · 5H2O |
| 3 photos of Schröckingerite associated with Gypsum | CaSO4 · 2H2O |
Related Minerals - Strunz-mindat Grouping
| 5.EG.05 | 'UM1997-27-CO:CaHKSU' | KCa3(UO2)(CO3)3(SO4)F · 10H2O |
| 5.EG.10 | Lepersonnite-(Gd) | Ca(Gd,Dy)2(UO2)24(SiO4)4(CO3)8(OH)24 · 48H2O |
| 5.EG.10 | Lepersonnite-(Nd) | Nd4(UO2)24(SiO4)4(CO3)8(OH)28 · 48H2O |
| 5.EG.15 | Ježekite | Na8[(UO2)(CO3)3](SO4)2 · 3H2O |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 26.7902% | 6,697,550 | 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 Schröckingerite
Strong yellow-green fluorescence. Not phosphorescent.
Other Information
Thermal Behaviour:
Heated in a closed tube it yields abundant water with neutral pH. Heated on charcoal before the blowpipe, it intumesces while giving off water and leaves a brown infusible residue. Fused with soda it gives a mass that darkens silver.
Notes:
Easily and completely soluble in acid. Completely soluble in water at room temperature (20 C).
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 Schröckingerite
mindat.org URL:
https://www.mindat.org/min-3584.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Schröckingerite
Reference List:
Armstrong, E. J. (1935) Schroeckingerite from Bedford, New York. American Mineralogist, 20 (1). 62-63
Larsen, Esper S., Gonyer, F. A. (1937) Dakeite, a new uranium mineral from Wyoming. American Mineralogist, 22 (5) 561-563 (as dakeite)
Nováček, Radim (1939) The identity of dakeite and schroeckingerite. American Mineralogist, 24 (5). 317-323
Jaffe, Howard W., Sherwood, Alexander M., Peterson, Maurice J. (1948) New data on schroeckingerite. American Mineralogist, 33 (3-4) 152-157
Axelrod, Joseph M., Grimaldi, Frank S., Milton, Charles, Murata, and K. J. (1951) The uranium minerals from the Hillside Mine, Yavapai County, Arizona. American Mineralogist, 36 (1-2) 1-22
Hurlbut, Cornelius S. Jr. (1954) Studies of uranium minerals (XV): Schroeckingerite from Argentina and Utah. American Mineralogist, 39 (11-12) 901-907
Frondel, Clifford (1958) Systematic mineralogy of uranium and thorium. Bulletin 1064. US Geological Survey doi:10.3133/b1064 pp.121-126
Smith, Deane K. (1959) X-ray crystallographic study of schroeckingerite and its dehydration product. American Mineralogist, 44 (9-10) 1020-1025
Sheridan, D. M.; Maxwell, C. H.; Collier, J. T. (1961) Geology of the Lost Creek schroeckingerite deposits, Sweetwater County, Wyoming. Bulletin 1087j. US Geological Survey doi:10.3133/b1087j
Barczak, V. J. (1966) Schroeckingerite from Ambrosia Lake uranium district. American Mineralogist, 51 (5-6) 929-930
Urbanec, Zdeněk, Čejka, Jiří (1979) Infrared spectra of liebigite, andersonite, voglite and schroeckingerite. Collection of Czechoslovak Chemical Communications, 44. 10-23 doi:10.1135/cccc19790010
O'Brien, Timothy J., Williams, Peter A. (1983) The aqueous chemistry of uranium minerals. 4. Schröckingerite, grimselite, and related alkali uranyl carbonates. Mineralogical Magazine, 47 (342) 69-73 doi:10.1180/minmag.1983.047.342.12
Mereiter, K. (1986) Crystal structure and crystallographic properties of a Schröckingerite from Joachimsthal. TMPM Tschermaks Mineralogische und Petrographische Mitteilungen, 35 (1) 1-18 doi:10.1007/bf01081914
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
Localities for Schröckingerite
Showing 165 localities.
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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.
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Svornost Mine, Jáchymov, Karlovy Vary District, Karlovy Vary Region, Czech Republic