Urancalcarite
A valid IMA mineral species
This page is currently not sponsored. Click here to sponsor this page.
About Urancalcarite
Formula:
Ca(UO2)3(CO3)(OH)6 · 3H2O
Colour:
Light yellow, bright yellow
Lustre:
Vitreous
Hardness:
2 - 3
Specific Gravity:
4.03
Crystal System:
Orthorhombic
Name:
The name reflects its composition: uranyl plus calcareous components.
This page provides mineralogical data about Urancalcarite.
Unique Identifiers
Mindat ID:
4101
Long-form identifier:
mindat:1:1:4101:6
IMA Classification of Urancalcarite
Approved
IMA Formula:
Ca(U6+O2)3CO3(OH)6·3H2O
Approval year:
1983
Classification of Urancalcarite
5.EA.10
5 : CARBONATES (NITRATES)
E : Uranyl Carbonates
A : UO2:CO3 > 1:1
5 : CARBONATES (NITRATES)
E : Uranyl Carbonates
A : UO2:CO3 > 1:1
16b.5.2.1
16b : HYDRATED CARBONATES CONTAINING HYDROXYL OR HALOGEN
5 : AmBn(XO3)pZqxH2O & with (m+n):p = 4:1
16b : HYDRATED CARBONATES CONTAINING HYDROXYL OR HALOGEN
5 : AmBn(XO3)pZq
11.11.9
11 : Carbonates
11 : Carbonates of Cr and U
11 : Carbonates
11 : Carbonates of Cr and 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 |
|---|---|---|
| Uca | 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 Urancalcarite
Vitreous
Transparency:
Transparent
Colour:
Light yellow, bright yellow
Streak:
Pale yellow
Hardness:
2 - 3 on Mohs scale
Cleavage:
None Observed
Density:
4.03 g/cm3 (Measured) 4.10 g/cm3 (Calculated)
Optical Data of Urancalcarite
Type:
Biaxial (-)
RI values:
nα = 1.660(3) nβ = 1.712(2) nγ = 1.736(2)
2V:
Measured: 67° , Calculated: 66°
Max. Birefringence:
δ = 0.076
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.
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:
weak
Chemistry of Urancalcarite
Mindat Formula:
Ca(UO2)3(CO3)(OH)6 · 3H2O
Element Weights:
Crystallography of Urancalcarite
Crystal System:
Orthorhombic
Cell Parameters:
a = 15.42(3) Å, b = 16.08(4) Å, c = 6.970(6) Å
Ratio:
a:b:c = 0.959 : 1 : 0.433
Unit Cell V:
1,728.24 ų (Calculated from Unit Cell)
Z:
4
Comment:
Point Group: 2/m 2/m 2/m or mm2.; Space Group: P bnm or P bn21
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.06 Å | (100) |
| 4.02 Å | (80) |
| 3.488 Å | (70) |
| 3.193 Å | (50) |
| 2.101 Å | (50) |
| 2.829 Å | (40) |
| 7.00 Å | (30) |
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] |
Type Occurrence of Urancalcarite
Place of Conservation of Type Material:
Royal Museum of Central Africa, Tervuren, Belgium, RGM13995.
Associated Minerals at Type Locality:
Synonyms of Urancalcarite
Other Language Names for Urancalcarite
Common Associates
Associations Based on Photo Data:
| 3 photos of Urancalcarite associated with Wyartite | CaU5+(UO2)2(CO3)O4(OH) · 7H2O |
| 3 photos of Urancalcarite associated with Uranophane | Ca(UO2)2(SiO3OH)2 · 5H2O |
| 2 photos of Urancalcarite associated with Gypsum | CaSO4 · 2H2O |
| 2 photos of Urancalcarite associated with Rameauite | K2Ca(UO2)6O6(OH)4 · 6H2O |
| 1 photo of Urancalcarite associated with Liebigite | Ca2(UO2)(CO3)3 · 11H2O |
| 1 photo of Urancalcarite associated with Agrinierite | K2(Ca,Sr)[(UO2)3O3(OH)2]2 · 5H2O |
Related Minerals - Strunz-mindat Grouping
| 5.EA.05 | 'UM1997-24-CO:CaCuHU' | Ca2Cu(UO2)2(CO3)2O3 · 3H2O |
| 5.EA.15 | Wyartite | CaU5+(UO2)2(CO3)O4(OH) · 7H2O |
| 5.EA.20 | Oswaldpeetersite | (UO2)2(CO3)(OH)2 · 4H2O |
| 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) | 66.9712% | 16,742,800 | 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
Notes:
Radioactive
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 Urancalcarite
mindat.org URL:
https://www.mindat.org/min-4101.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Urancalcarite
Reference List:
Deliens, Michel, Piret, Paul (1984) L'urancalcarite, Ca(UO2)3CO3(OH)6.3H2O, nouveau minéral de Shinkolobwe, Shaba, Zaïre. Bulletin de Minéralogie, 107 (1) 21-24 doi:10.3406/bulmi.1984.7789
Localities for Urancalcarite
Showing 7 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 | |
| Wang (1992) |
Czech Republic | |
| Hloušek et al. (2002) |
DR Congo (TL) | |
| Deliens et al. (1984) +1 other reference |
France | |
| Chuck Adan Collection |
| Caubel (1997) |
Norway | |
| Roy Kristiansen (1989) +1 other reference |
Romania | |
| Hîrtopanu P. et al. (2004) |
Quick NavTopAbout UrancalcariteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatRadioactivityOther InformationInternet Links References Localities Locality List
Shinkolobwe Mine, Shinkolobwe, Kambove Territory, Haut-Katanga, DR Congo