Oswaldpeetersite
A valid IMA mineral species
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About Oswaldpeetersite
Oswald Peeters
Formula:
(UO2)2(CO3)(OH)2 · 4H2O
Colour:
Canary yellow
Lustre:
Vitreous
Hardness:
2 - 3
Specific Gravity:
4.1 - 4.55
Crystal System:
Monoclinic
Name:
Named in honor of Maurice Oswald Peeters (b. 2 March 1945, Leuven, Belgium, died 9 June 2026), structural crystallographer at the University of Leuven, Belgium and researcher in the field of uranium mineralogy.
This page provides mineralogical data about Oswaldpeetersite.
Unique Identifiers
Mindat ID:
10997
Long-form identifier:
mindat:1:1:10997:2
IMA Classification of Oswaldpeetersite
Approved
IMA Formula:
(U6+O2)2CO3(OH)2·4H2O
Approval year:
2000
First published:
2001
Classification of Oswaldpeetersite
5.EA.20
5 : CARBONATES (NITRATES)
E : Uranyl Carbonates
A : UO2:CO3 > 1:1
5 : CARBONATES (NITRATES)
E : Uranyl Carbonates
A : UO2:CO3 > 1:1
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 |
|---|---|---|
| Osw | 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 Oswaldpeetersite
Vitreous
Transparency:
Transparent
Colour:
Canary yellow
Streak:
Pale yellow
Hardness:
2 - 3 on Mohs scale
Hardness Data:
Estimated
Parting:
Along the elongation.
Fracture:
Irregular/Uneven
Comment:
The tenacity is described as weak.
Density:
4.1 - 4.55 g/cm3 (Measured) 4.55 g/cm3 (Calculated)
Comment:
Measured greater than 4.1.
Optical Data of Oswaldpeetersite
Type:
Biaxial (-)
RI values:
nα = 1.583(2) nβ = 1.669(2) nγ = 1.712(2)
2V:
Calculated: 67.4°
Max. Birefringence:
δ = 0.129
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
Dispersion:
None observed
Optical Extinction:
Z = a. Elongation is positive.
Pleochroism:
Weak
Comments:
X = Y = very pale yellow to colorless; Z = pale yellow.
Chemistry of Oswaldpeetersite
Mindat Formula:
(UO2)2(CO3)(OH)2 · 4H2O
Element Weights:
Elements listed:
Crystallography of Oswaldpeetersite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Cell Parameters:
a = 4.1425 Å, b = 14.098 Å, c = 18.374 Å
β = 103.62°
β = 103.62°
Ratio:
a:b:c = 0.294 : 1 : 1.303
Unit Cell V:
1042.8 ų
Z:
4
Twinning:
None mentioned.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.32 Å | (100) |
| 4.55 Å | (96) |
| 3.029 Å | (85) |
| 8.95 Å | (65) |
| 7.54 Å | (63) |
| 3.46 Å | (62) |
| 2.273 Å | (62) |
| 4.26 Å | (60) |
Comments:
Jomac mine, Utah, USA. The data are from the type description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] | |
| 47f : [Uranyl (U⁶⁺) minerals] | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 53 : Other minerals with taphonomic origins | <0.4 |
Type Occurrence of Oswaldpeetersite
General Appearance of Type Material:
Micrometric prismatic crystals arranged in radiating groups.
Place of Conservation of Type Material:
Royal Belgian Institute of Natural Sciences, Brussels.
Geological Setting of Type Material:
Triassic conglomerate rich in organic material such as black coal-bearing smears and logs of partially petrified wood.
Associated Minerals at Type Locality:
Synonyms of Oswaldpeetersite
Other Language Names for Oswaldpeetersite
Related Minerals - Strunz-mindat Grouping
| 5.EA.05 | 'UM1997-24-CO:CaCuHU' | Ca2Cu(UO2)2(CO3)2O3 · 3H2O |
| 5.EA.10 | Urancalcarite | Ca(UO2)3(CO3)(OH)6 · 3H2O |
| 5.EA.15 | Wyartite | CaU5+(UO2)2(CO3)O4(OH) · 7H2O |
| 5.EA.25 | Roubaultite | Cu2(UO2)3(CO3)2O2(OH)2 · 4H2O |
| 5.EA.30 | Kamotoite-(Y) | Y2(UO2)4(CO3)3O4 · 14H2O |
| 5.EA.35 | Sharpite | Ca(UO2)3(CO3)4 · 3H2O |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 67.4169% | 16,854,225 | 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 Oswaldpeetersite
Does not fluoresce under 360 nm light; this contrasts with joliotite, which strongly fluoresces, and with blatonite, which strongly fluoresces greenish yellow in ultraviolet radiation.
Other Information
Notes:
Soluble with effervescence in dilute HCl.
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 Oswaldpeetersite
mindat.org URL:
https://www.mindat.org/min-10997.html
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References for Oswaldpeetersite
Reference List:
Vochten, R., Deliens, M., Medenbach, O. (2001) Oswaldpeetersite, (UO2)2CO3(OH)2·4H2O, a new basic uranyl carbonate mineral from the Jomac uranium mine, San Juan County, Utah, U.S.A. The Canadian Mineralogist, 39 (6) 1685-1689 doi:10.2113/gscanmin.39.6.1685
Localities for Oswaldpeetersite
Showing 3 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.
China | |
| Ding et al. (2023) |
USA | |
| Caldwell (2018) |
| Vochten et al. (2001) |
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Jomac Mine, White Canyon Mining District, San Juan County, Utah, USA