Wyartite
A valid IMA mineral species
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About Wyartite
Jean Wyart
Formula:
CaU5+(UO2)2(CO3)O4(OH) · 7H2O
Colour:
Black, violet-black (fresh); yellowish brown, greenish brown (exposed)
Lustre:
Vitreous, Sub-Metallic, Dull
Hardness:
3 - 4
Specific Gravity:
4.69
Crystal System:
Orthorhombic
Name:
Named after Jean Wyart (16 October 1902, Avion, Pas-de-Calais, France - 13 March 1992, Paris, France), Professor of Mineralogy, Sorbonne, Paris, France.
Wyartite is unique in being the first recognized mineral with pentavalent uranium, beside containing typical hexavalent one in the form of uranyl groups. Other minerals sharing this feature include richetite, shinkolobweite, and nollmotzite.
The structure contains sheets that are similar to those found in ianthinite, rameauite, and spriggite.
The structure contains sheets that are similar to those found in ianthinite, rameauite, and spriggite.
Unique Identifiers
Mindat ID:
4319
Long-form identifier:
mindat:1:1:4319:5
Similar Names
| Wyartite II | A synonym of 'Dehydrated wyartite' |
IMA Classification of Wyartite
Approved
IMA Formula:
CaU5+(U6+O2)2(CO3)O4(OH)·7H2O
First published:
1959
Classification of Wyartite
5.EA.15
5 : CARBONATES (NITRATES)
E : Uranyl Carbonates
A : UO2:CO3 > 1:1
5 : CARBONATES (NITRATES)
E : Uranyl Carbonates
A : UO2:CO3 > 1:1
16b.7.4.1
16b : HYDRATED CARBONATES CONTAINING HYDROXYL OR HALOGEN
7 : Miscellaneous
16b : HYDRATED CARBONATES CONTAINING HYDROXYL OR HALOGEN
7 : Miscellaneous
11.11.8
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 |
|---|---|---|
| Wya | 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 Wyartite
Vitreous, Sub-Metallic, Dull
Transparency:
Transparent, Translucent, Opaque
Comment:
Luster dull, on cleavage vitreous to sub-metallic
Colour:
Black, violet-black (fresh); yellowish brown, greenish brown (exposed)
Comment:
Wyartite is somewhat photosensitive and may change from nearly black when exposed to light to dark brown to brownish-orange. Crystals end frequently brighten ahead of the crystal shafts.
Streak:
Brownish-violet
Hardness:
3 - 4 on Mohs scale
Cleavage:
Perfect
(001) perfect, also (010)
(001) perfect, also (010)
Density:
4.69(5) g/cm3 (Measured)
Optical Data of Wyartite
Type:
Biaxial (-)
RI values:
nα = 1.89(2) nβ = 1.89(2) nγ = 1.91(2)
2V:
Measured: 48°
Max. Birefringence:
δ = 0.020
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:
strong
Pleochroism:
Strong
Comments:
X (=c) gray, Y (=b) violet, Z (=a) (lavender blue) .
Chemistry of Wyartite
Mindat Formula:
CaU5+(UO2)2(CO3)O4(OH) · 7H2O
Element Weights:
Crystallography of Wyartite
Crystal System:
Orthorhombic
Class (H-M):
222 - Disphenoidal
Space Group:
P212121
Cell Parameters:
a = 11.25(3) Å, b = 7.08(2) Å, c = 20.98(5) Å
Ratio:
a:b:c = 1.589 : 1 : 2.963
Unit Cell V:
1,671.06 ų (Calculated from Unit Cell)
Z:
4
Comment:
Point Group: 2/m 2/m 2/m?
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
Remove metal-metal sticks
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
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) |
|---|---|---|---|---|---|---|---|
| 0006129 | Wyartite | Hawthorne F C, Finch R J, Ewing R C (2006) The crystal structure of dehydrated wyartite, Ca(CO3)[U5+(U6+O2)2O4(OH)] (H2O)3 The Canadian Mineralogist 44 1379-1385 |  | 2006 | Shinkolobwe mine, Shaba, Democratic Republic of Congo | 0 | 293 |
| 0002316 | Wyartite | Burns P C, Finch R J (1999) Wyartite: Crystallographic evidence for the first pentavalent-uranium mineral American Mineralogist 84 1456-1460 | | 1999 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 10.3 Å | (100) |
| 8.54 Å | (30) |
| 5.19 Å | (30) |
| 4.26 Å | (4b) |
| 3.55 Å | (4) |
| 7.64 Å | (3) |
| 4.72 Å | (3) |
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 Wyartite
General Appearance of Type Material:
In small crystals with (001) predominant, striated, and (110)
Place of Conservation of Type Material:
Royal Museum of Central Africa, Tervuren, Belgium, RMG2222; Natural History Museum, Paris, France, V 5686; National School of Mines, Paris, France; The Natural History Museum, London, England, 1969,47; National Museum of Natural History, Washington, D.C., USA, 150331.
Geological Setting of Type Material:
as an alteration product of a red alteration product of uraninite (wolsendorfite?)
Synonyms of Wyartite
Other Language Names for Wyartite
Common Associates
Associations Based on Photo Data:
| 3 photos of Wyartite associated with Uraninite | UO2 |
| 3 photos of Wyartite associated with Urancalcarite | Ca(UO2)3(CO3)(OH)6 · 3H2O |
| 3 photos of Wyartite associated with Uranophane | Ca(UO2)2(SiO3OH)2 · 5H2O |
| 2 photos of Wyartite associated with Shinkolobweite | Pb1.333[U5+O(OH)(UO2)5O4.67(OH)5.33](H2O)5 |
| 1 photo of Wyartite associated with Wölsendorfite | Pb7(UO2)14O19(OH)4 · 12H2O |
| 1 photo of Wyartite associated with Rutherfordine | (UO2)CO3 |
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.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) | 65.7973% | 16,449,325 | 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 Wyartite
mindat.org URL:
https://www.mindat.org/min-4319.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Wyartite
Reference List:
Guillemin, Claude; Protas, Jean (1959) Ianthinite et wyartite. Bulletin de la Société française de Minéralogie et de Cristallographie, 82 (1). 80-86 doi:10.3406/bulmi.1959.5308
Guillemin, Claude; Protas, Jean (1959) Ianthinite et wyartite. Bulletin de la Société française de Minéralogie et de Cristallographie, 82 (1). 80-86 doi:10.3406/bulmi.1959.5308
Burns, Peter C., Finch, Robert J. (1999) Wyartite; crystallographic evidence for the first pentavalent-uranium mineral. American Mineralogist, 84 (9) 1456-1460 doi:10.2138/am-1999-0926
Frost, Ray L., Henry, Dermot A., Erickson, Kristy (2004) Raman spectroscopic detection of wyartite in the presence of rabejacite. Journal of Raman Spectroscopy, 35 (4). 255-260 doi:10.1002/jrs.1144
Localities for Wyartite
Showing 10 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.
Australia | |
| Frost et al. (2004) |
| Frost et al. (2004) | |
| Habibi et al. (2026) |
| Habibi et al. (2025) |
DR Congo (TL) | |
| 304 [288]. +3 other references |
France | |
| - (1998) |
| J.-J. Périchaud: "Où trouver les minéraux d'Auvergne" et al. (Clermont-Ferrand) | |
India | |
| Yadav et al. (2008) |
| Yadav et al. (2008) | |
Jordan | |
| Dill et al. (2009) |
Quick NavTopAbout WyartiteUnique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatRadioactivityOther InformationInternet Links References Localities Locality List
Shinkolobwe Mine, Shinkolobwe, Kambove Territory, Haut-Katanga, DR Congo