Lepersonnite-(Nd)
A valid IMA mineral species
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About Lepersonnite-(Nd)
Formula:
Nd4(UO2)24(SiO4)4(CO3)8(OH)28 · 48H2O
Colour:
yellow
Hardness:
1½
Specific Gravity:
4.12 (Calculated)
Crystal System:
Orthorhombic
Name:
Named for being the neodymium analogue of lepersonnite-(Gd).
Type Locality:
Isostructural with:
Unique Identifiers
Mindat ID:
55684
Long-form identifier:
mindat:1:1:55684:2
Similar Names
| Lepersonnite-(Gd) | A valid IMA mineral species | Ca(Gd,Dy)2(UO2)24(SiO4)4(CO3)8(OH)24 · 48H2O |
IMA Classification of Lepersonnite-(Nd)
Approved
IMA Formula:
[Nd(H2O)18(OH)2][Nd(U6+O2)12(SiO3OH)2(CO3)4(OH)10O2(H2O)5]
Classification of Lepersonnite-(Nd)
5.EG.10
5 : CARBONATES (NITRATES)
E : Uranyl Carbonates
G : With SO4 or SiO4
5 : CARBONATES (NITRATES)
E : Uranyl Carbonates
G : With SO4 or SiO4
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 |
|---|---|---|
| Lps-Nd | 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 Lepersonnite-(Nd)
Colour:
Yellow
Streak:
Pale yellow
Hardness:
1½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
multiple cleavages have been observed, but it is hard to
determine the crystallographic orientations due to the intergrown nature of crystal aggregates.
multiple cleavages have been observed, but it is hard to
determine the crystallographic orientations due to the intergrown nature of crystal aggregates.
Density:
4.12 g/cm3 (Calculated)
Optical Data of Lepersonnite-(Nd)
Type:
Biaxial (-)
RI values:
nα = 1.621(3) nβ = 1.657(3) nγ = 1.677(3)
2V:
Measured: 68° (5), Calculated: 72°
Max. Birefringence:
δ = 0.056
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:
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:
not observed
Orientation:
X = a, Y = c, Z = b.
Pleochroism:
Visible
Comments:
X = yellow, Y = yellow, Z = light yellow;
Chemistry of Lepersonnite-(Nd)
Mindat Formula:
Nd4(UO2)24(SiO4)4(CO3)8(OH)28 · 48H2O
Element Weights:
Crystallography of Lepersonnite-(Nd)
Crystal System:
Orthorhombic
Cell Parameters:
a = 11.7189(7) Å, b = 17.1013(7) Å, c = 38.681(2) Å
Ratio:
a:b:c = 0.685 : 1 : 2.262
Unit Cell V:
7,752.00 ų (Calculated from Unit Cell)
Z:
4
Comment:
Space group is Pnnm or Pnn2 The small size, somewhat poor quality, and intergrown nature (see the discussion section) of lepersonnite-(Nd) crystals made structure determination through X-ray singlecrystal diffraction study impossible.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.16 Å | (100) |
| 3.66 Å | (57) |
| 3.20 Å | (33) |
| 3.11 Å | (21) |
| 3.01 Å | (21) |
| 2.86 Å | (22) |
| 1.956 Å | (20) |
| 1.902 Å | (23) |
Type Occurrence of Lepersonnite-(Nd)
General Appearance of Type Material:
radial to acicular aggregates composed of long prismatic, thin crystals, as the products of hydration-oxidation weathering of uraninite.
Place of Conservation of Type Material:
mineralogical collections of (1) the Musée d’Histoire Naturelle, 25 rue Münster, L-2160 Luxembourg, Luxembourg, specimen no. WPV020, and (2) the Royal Museum for Central Africa, Leuvensesteenweg 13, 3080 Tervuren, Belgium, specimen no. RGM11529.1
Geological Setting of Type Material:
hydration-oxidation weathering of uraninite
Associated Minerals at Type Locality:
Other Language Names for Lepersonnite-(Nd)
Dutch:Lepersonniet-(Nd)
German:Lepersonnit-(Nd)
Common Associates
Associations Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
| 5.EG.05 | Schröckingerite | NaCa3(UO2)(CO3)3(SO4)F · 10H2O |
| 5.EG.05 | 'UM1997-27-CO:CaHKSU' | KCa3(UO2)(CO3)3(SO4)F · 10H2O |
| 5.EG.10 | Lepersonnite-(Gd) | Ca(Gd,Dy)2(UO2)24(SiO4)4(CO3)8(OH)24 · 48H2O |
| 5.EG.15 | Ježekite | Na8[(UO2)(CO3)3](SO4)2 · 3H2O |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 61.7791% | 15,444,775 | 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 Lepersonnite-(Nd)
non-fluorescent in SW and LW ultraviolet light
Other Information
Notes:
Lepersonnite-(Nd) is soluble in dilute hydrochloric acid (10 %), releasing CO₂ and leaving a residue of amorphous silica.
Health Risks:
radioactive
Internet Links for Lepersonnite-(Nd)
mindat.org URL:
https://www.mindat.org/min-55684.html
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Please feel free to link to this page.
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References for Lepersonnite-(Nd)
Localities for Lepersonnite-(Nd)
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 | |
| Plášil J et al. (2025) |
| Miyawaki et al. (2021) +1 other reference |
Quick NavTopAbout Lepersonnite-(Nd)Unique IdentifiersSimilar NamesIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography X-Ray Powder DiffractionType Occurrence Other LanguagesCommon AssociatesStrunz-MindatRadioactivityFluorescence Other InformationInternet Links References Localities Locality List
Swambo Hill, Kambove Territory, Haut-Katanga, DR Congo