Moreauite
A valid IMA mineral species
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About Moreauite
Formula:
Al3(UO2)(PO4)3(OH)2 · 13H2O
Colour:
Greenish yellow
Lustre:
Vitreous
Specific Gravity:
2.64
Crystal System:
Monoclinic
Name:
For Belgian mineralogist, Jules Moreau (28/01/1931 Nimy, Hainaut Province, Belgium - 28/12/2015 Hamme-Mille, Walloon Brabant Province, Belgium), Belgian mineralogist, professor of mineralogy at the University of Louvain-la-Neuve, Belgium.
Type Locality:
This page provides mineralogical data about Moreauite.
Unique Identifiers
Mindat ID:
2780
Long-form identifier:
mindat:1:1:2780:5
Similar Names
IMA Classification of Moreauite
Approved
IMA Formula:
Al3(U6+O2)(PO4)3(OH)2·13H2O
Approval year:
1984
First published:
1985
Classification of Moreauite
8.ED.05
8 : PHOSPHATES, ARSENATES, VANADATES
E : Uranyl phosphates and arsenates
D : Unclassified
8 : PHOSPHATES, ARSENATES, VANADATES
E : Uranyl phosphates and arsenates
D : Unclassified
42.12.3.1
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
12 : (AB)4(XO4)3Zq·xH2O
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
12 : (AB)4(XO4)3Zq·xH2O
19.11.30
19 : Phosphates
11 : Phosphates of U
19 : Phosphates
11 : Phosphates 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 |
|---|---|---|
| Moa | 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 Moreauite
Vitreous
Transparency:
Translucent, Opaque
Colour:
Greenish yellow
Cleavage:
Distinct/Good
Good on {100}, micaceous.
Good on {100}, micaceous.
Density:
2.64(5) g/cm3 (Measured) 2.61 g/cm3 (Calculated)
Optical Data of Moreauite
Type:
Biaxial (-)
RI values:
nα = 1.540(3) nβ = 1.552(2) nγ = 1.558(2)
2V:
Measured: 70° , Calculated: 70°
Max. Birefringence:
δ = 0.018
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:
Low (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 Moreauite
Mindat Formula:
Al3(UO2)(PO4)3(OH)2 · 13H2O
Element Weights:
Crystallography of Moreauite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/c
Cell Parameters:
a = 23.41(6) Å, b = 21.44(4) Å, c = 18.34(3) Å
β = 92.0(1)°
β = 92.0(1)°
Ratio:
a:b:c = 1.092 : 1 : 0.855
Unit Cell V:
9,199.43 ų (Calculated from Unit Cell)
Z:
16
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 10.80 Å | (100) |
| 11.69 Å | (80) |
| 9.13 Å | (70) |
| 2.931 Å | (70) |
| 14.02 Å | (60) |
| 3.043 Å | (60) |
| 5.43 Å | (40) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 22 : Hydration and low-? subsurface aqueous alteration (see also #23) |
Type Occurrence of Moreauite
General Appearance of Type Material:
Nodules and books of plates flattened on (100).
Place of Conservation of Type Material:
Royal Museum for Central Africa, Tervuren
Geological Setting of Type Material:
Uranium-bearing oxidized zone of a complex granite pegmatite.
Associated Minerals at Type Locality:
Synonyms of Moreauite
Other Language Names for Moreauite
Related Minerals - Strunz-mindat Grouping
| 8.ED.10 | Šreinite | Pb(BiO)3(UO2)4(PO4)2(OH)7 · 4H2O |
| 8.ED.10 | Metalodèvite | Zn(UO2)2(AsO4)2 · 10H2O |
| 8.ED.10 | Asselbornite | Pb(BiO)3(UO2)4(AsO4)2(OH)7 · 4H2O |
| 8.ED.15 | Kamitugaite | PbAl[(UO2)5(PO4)2.38(AsO4)0.62O2(OH)2] · 11.5H2O |
| 8.ED.20 | Nielsbohrite | K(UO2)3(AsO4)(OH)4 · H2O |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 26.3277% | 6,581,925 | 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 Moreauite
bright green fluorescence under SW and LW
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 Moreauite
mindat.org URL:
https://www.mindat.org/min-2780.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 Moreauite
Reference List:
Deliens, Michel, Piret, Paul (1985) Les phosphates d'uranyle et d'aluminium de Kobokobo. VII. La moreauïte, Al3UO2(PO4)3(OH)2·13H2O, nouveau minéral. Bulletin de Minéralogie, 108 (1) 9-13 doi:10.3406/bulmi.1985.7853
Dunn, Pete J., Ferraiolo, James A., Fleischer, Michael, Gobel, Volker, Grice, Joel D., Langley, Richard H., Shigley, James E., Vanko, David A., Zilczer, Janet A. (1985) New mineral names. American Mineralogist, 70 (11-12) 1329-1335
Localities for Moreauite
Showing 2 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.
DR Congo (TL) | |
| Deliens et al. (1985) +1 other reference |
Spain | |
| www.foro-minerales.com (n.d.) |
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Valdeíñigos, Tejeda de Tiétar, Cáceres, Extremadura, Spain