Cuprosklodowskite
A valid IMA mineral species - grandfathered
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About Cuprosklodowskite
Formula:
Cu(UO2)2(SiO3OH)2 · 6H2O
Colour:
Yellowish green to grass green or greenish yellow
Lustre:
Silky, Dull
Hardness:
4
Specific Gravity:
3.85
Crystal System:
Triclinic
Member of:
Name:
Named as the copper analogue of sklodowskite.
Type Locality:
This page provides mineralogical data about Cuprosklodowskite.
Unique Identifiers
Mindat ID:
1191
Long-form identifier:
mindat:1:1:1191:0
IMA Classification of Cuprosklodowskite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Cu2+(U6+O2)2(SiO3OH)2·6H2O
First published:
1933
Classification of Cuprosklodowskite
9.AK.10
9 : SILICATES (Germanates)
A : Nesosilicates
K : Uranyl neso- and polysilicates
9 : SILICATES (Germanates)
A : Nesosilicates
K : Uranyl neso- and polysilicates
53.3.1.4
53 : NESOSILICATES Insular SiO4 Groups and Other Anions or Complex Cations
3 : Insular SiO4 Groups and Other Anions of Complex Cations with (UO2)
53 : NESOSILICATES Insular SiO4 Groups and Other Anions or Complex Cations
3 : Insular SiO4 Groups and Other Anions of Complex Cations with (UO2)
14.16.8
14 : Silicates not Containing Aluminum
16 : Silicates of U
14 : Silicates not Containing Aluminum
16 : Silicates of U
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 |
|---|---|---|
| Cskl | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of Cuprosklodowskite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Cuprosklodowskite
Silky, Dull
Transparency:
Transparent, Translucent
Colour:
Yellowish green to grass green or greenish yellow
Hardness:
4 on Mohs scale
Cleavage:
Distinct/Good
{100}
{100}
Density:
3.85(2) g/cm3 (Measured) 3.89 g/cm3 (Calculated)
Comment:
Calculated density from Plášil (2018)
Optical Data of Cuprosklodowskite
Type:
Biaxial (-)
RI values:
nα = 1.654 - 1.655 nβ = 1.664 - 1.667 nγ = 1.664 - 1.667
Max. Birefringence:
δ = 0.010 - 0.012
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:
Very High (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.
No measured or calculated 2V is on file for this mineral, so the value used here (-0°) 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 (-0°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
r > v
Pleochroism:
Visible
Comments:
X= nearly colorless
Y=Z= yellowish green
Y=Z= yellowish green
Chemistry of Cuprosklodowskite
Mindat Formula:
Cu(UO2)2(SiO3OH)2 · 6H2O
Element Weights:
Crystallography of Cuprosklodowskite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 6.6549(5) Å, b = 7.0573(4) Å, c = 9.2344(8) Å
α = 70.429(6)°, β = 70.945(7)°, γ = 89.850(5)°
α = 70.429(6)°, β = 70.945(7)°, γ = 89.850(5)°
Ratio:
a:b:c = 0.943 : 1 : 1.308
Unit Cell V:
383.47 ų (Calculated from Unit Cell)
Z:
1
Morphology:
Needles. Forms include {110}, {100}, and rarely {010}; frequently terminated by {0kl}, probably {031}.
Comment:
Cell parameters from Plášil (2018) with R1=3.75%.
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
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Polyhedra Off | Si Polyhedra | All Polyhedra
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View
CIF File Best | x | y | z | a | b | c
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Labels
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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) |
|---|---|---|---|---|---|---|---|
| 0000461 | Cuprosklodowskite | Rosenzweig A, Ryan R R (1975) Refinement of the crystal structure of cuprosklodowskite, Cu[(UO2)2(SiO3OH)2]*6(H2O) American Mineralogist 60 448-453 |  | 1975 | Musonoi mine, Kolwezi, Katanga, Zaire | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.18 Å | (100) |
| 4.09 Å | (90) |
| 2.97 Å | (80) |
| 4.82 Å | (70) |
| 3.52 Å | (60) |
| 2.21 Å | (60) |
| 2.72 Å | (50) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47f : [Uranyl (U⁶⁺) minerals] |
Geological Setting:
Secondary mineral in uranium deposits
Type Occurrence of Cuprosklodowskite
General Appearance of Type Material:
Small acicular needles.
Place of Conservation of Type Material:
University of Liµege, Liµege, Belgium, 16.655.
Geological Setting of Type Material:
Uranium deposit; in a fissure in a talcose argillaceous rock.
Synonyms of Cuprosklodowskite
Other Language Names for Cuprosklodowskite
Dutch:Cuprosklodowskiet
Japanese:銅スクロドフスカ石
Russian:Купросклодовскит
Simplified Chinese:硅铜铀矿
Spanish:Cuprosklodovskita
Relationship of Cuprosklodowskite to other Species
Member of:
Other Members of Sklodowskite Group:
| Oursinite | Co(UO2)2(SiO3OH)2 · 6H2O | Orth. mmm(2/m2/m2/m) : Cmca |
| Sklodowskite | Mg(UO2)2(SiO3OH)2 · 6H2O | Mon. 2/m : B2/m |
Common Associates
Associations Based on Photo Data:
| 113 photos of Cuprosklodowskite associated with Malachite | Cu2(CO3)(OH)2 |
| 59 photos of Cuprosklodowskite associated with Sklodowskite | Mg(UO2)2(SiO3OH)2 · 6H2O |
| 56 photos of Cuprosklodowskite associated with Vandenbrandeite | Cu(UO2)(OH)4 |
| 47 photos of Cuprosklodowskite associated with Rutherfordine | (UO2)CO3 |
| 47 photos of Cuprosklodowskite associated with Schoepite | (UO2)8O2(OH)12 · 12H2O |
| 44 photos of Cuprosklodowskite associated with Torbernite | Cu(UO2)2(PO4)2 · 12H2O |
| 42 photos of Cuprosklodowskite associated with Kasolite | Pb(UO2)(SiO4) · H2O |
| 38 photos of Cuprosklodowskite associated with Digenite | Cu9S5 |
| 38 photos of Cuprosklodowskite associated with Soddyite | (UO2)2SiO4 · 2H2O |
| 27 photos of Cuprosklodowskite associated with Uranophane | Ca(UO2)2(SiO3OH)2 · 5H2O |
Related Minerals - Strunz-mindat Grouping
| 9.AK. | 'Orlite' | Pb3(UO2)3(Si2O7)2 · 6H2O |
| 9.AK.05 | Soddyite | (UO2)2SiO4 · 2H2O |
| 9.AK.10 | Sklodowskite | Mg(UO2)2(SiO3OH)2 · 6H2O |
| 9.AK.10 | Oursinite | Co(UO2)2(SiO3OH)2 · 6H2O |
| 9.AK.15 | Parauranophane | Ca(UO2)2(SiO3OH)2 · 5H2O |
| 9.AK.15 | Uranophane | Ca(UO2)2(SiO3OH)2 · 5H2O |
| 9.AK.15 | Natroboltwoodite | Na(UO2)(SiO3OH) · H2O |
| 9.AK.15 | Kasolite | Pb(UO2)(SiO4) · H2O |
| 9.AK.15 | Boltwoodite | (K,Na)(UO2)(SiO3OH) · 1.5H2O |
| 9.AK.20 | Swamboite-(Nd) | Nd0.333[(UO2)(SiO3OH)](H2O)~2.5 |
| 9.AK.25 | Haiweeite | Ca(UO2)2[Si5O12(OH)2] · 6H2O |
| 9.AK.25 | Metahaiweeite | Ca(UO2)2Si6O15 · nH2O |
| 9.AK.30 | Weeksite | K2(UO2)2(Si5O13) · 4H2O |
| 9.AK.30 | Coutinhoite | ThxBa(1-2x)(UO2)2Si5O13 · (H2O)1+y (0 < x < 0.5 and 0 < y < (2+x)) |
| 9.AK.30 | Barronite | (◻0.5Ba0.5)(UO2)2Si5O12(OH) · 2H2O |
| 9.AK.35 | Magnioursilite | Mg4(UO2)4(Si2O5)5(OH)6 · 20H2O |
| 9.AK.35 | Calcioursilite | Ca4(UO2)4(Si2O5)5(OH)6 · 15H2O |
| 9.AK.40 | Uranosilite | UO3 · 7SiO2 |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 53.0205% | 13,255,125 | 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
Other Information
Health Risks:
Contains uranium - always wash hands after handling. Avoid inhaling dust when handling or breaking. Never lick or ingest. Avoid prolonged exposure in the proximity of the body. Store away from inhabited areas.
Internet Links for Cuprosklodowskite
mindat.org URL:
https://www.mindat.org/min-1191.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Cuprosklodowskite
Reference List:
Rosenweig, Abraham, Ryan, Robert R. (1975) Refinement of the crystal structure of cuprosklodowskite Cu[(UO2)2(SiO3OH)2]·6H2O. American Mineralogist, 60 (5-6) 448-453
Stohl, Frances V., Smith, Deane K. (1981) The crystal chemistry of the uranyl silicate minerals. American Mineralogist, 66 (5-6) 610-624
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
Frost, Ray L., Čejka, Jiří, Weier, Matt L, Martens, Wayde (2006) Molecular structure of the uranyl silicates—a Raman spectroscopic study. Journal of Raman Spectroscopy, 37 (4). 538-551 doi:10.1002/jrs.1430
Plášil, Jakub (2018) Mineralogy, Crystallography and Structural Complexity of Natural Uranyl Silicates. Minerals, 8 (12) 551 doi:10.3390/min8120551(with refinement of cuprosklodowskite)
Localities for Cuprosklodowskite
Showing 78 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.
Argentina | |
| Lucero et al. (1963) |
| Lucero et al. (1963) | |
| American Mineralogist: 46: 12-25. | |
| American Mineralogist: 51: 1-13 |
Canada | |
| Cowan (1962) |
| Hogarth (1951) |
Czech Republic | |
| Ondruš et al. (1989) +1 other reference |
| Pauliš P. et al. (Kutna Hora, issue 1) +1 other reference | |
| Duda |
| Möhn et al. (12/2021) | |
| Tvrdý et al. (2010) | |
| Plášil et al. (2014) | |
| Pauliš P. et al. (Kutna Hora, issue 1) |
| 70 (in German) +2 other references | |
| Sejkora et al. (2007) +1 other reference |
| Pauliš P. et al. (Kutna Hora, issue 1) |
| Pauliš P. et al. (Kutna Hora, issue 1) |
| Pauliš P. et al. (Kutna Hora, issue 1) |
DR Congo | |
| KMMA +2 other references |
| Deliens (1996) |
| KMMA +1 other reference |
| KMMA +2 other references |
| Anthony et al. (2003) |
| Anthony et al. (2003) | |
| KMMA | |
| KMMA |
| Daltry (1992) +3 other references | |
| |
France | |
| - (1998) |
| Bariand et al. (1993) +1 other reference |
| R. Pierrot |
| - (1998) | |
| - (1998) |
Germany | |
| Walenta (1992) |
| Aufschluss 1987 (8/9) +1 other reference |
| Gerhard Möhn Collection |
| Weiß (1990) |
| Dill et al. (2010) | |
| Desor (06/2020) |
| Lapis 30 (7/8) | |
Iran | |
| Khoshnoodi et al. (2025) |
| Iranmanesh et al. (2018) |
Italy | |
| Campostrini I. (2013) |
| Campostrini et al. (2006) |
| Campostrini et al. (2005) |
Japan | |
| Kato (1973) |
Mexico | |
| Megaw (2023) |
Morocco | |
| |
Poland | |
| Siuda R. et al. (2010) |
Spain | |
| Sainz de Baranda Graf (2026) |
| Abella et al. (2009) +1 other reference |
Sweden | |
| Natural History Museum |
| Löfvendahl (1981) |
| Löfvendahl (1981) | |
Switzerland | |
| |
| Stalder et al. (1998) |
| Stalder et al. (1998) |
| Ansermet (2012) |
UK | |
| P Haas |
| Golley et al. (1995) | |
| Golley et al. (1995) |
USA | |
| Murdoch (1966) |
| Troxel et al. (1957) +2 other references |
| Saul et al. (1970) +2 other references |
| Castor et al. (2004) |
| Northrop et al. (1996) |
| Northrop et al. (1996) | |
| NMBMMR Memoir 15 Geology and Technology ... +3 other references | |
| Northrop et al. (1996) | |
| Sun et al. (1958) |
| Northrop et al. (1996) |
| New Mexico Bureau of Mines and Mineral ... |
| Bullock (1981) |
| Bullock (1981) | |
| Min News 17:7 p1 | |
| Kampf et al. (2018) |
| Page et al. (1956) +3 other references | |
| Bullock (1981) |
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Musonoi Mine, Kolwezi, Mutshatsha, Lualaba, DR Congo