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Lepersonnite-(Gd)
A valid IMA mineral species
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About Lepersonnite-(Gd)
Jacques, Lambert, DÃĐsirÃĐ Lepersonne
Formula:
Ca(Gd,Dy)2(UO2)24(SiO4)4(CO3)8(OH)24 · 48H2O
Colour:
Bright yellow
Specific Gravity:
3.97
Crystal System:
Orthorhombic
Name:
After Jacques Lepersonne (Mulhouse, France October 26, 1909 - Etterbeek, Brussels, August 10, 1997); Royal Belgian Museum for Central Africa. He was honorary head of the Department of Geology and Mineralogy at the museum where the type specimens are preserved. The suffix was added in 1987.
Isostructural with:
Used to be a unique species in terms of gadolinium dominance. Currently third such (named; unnamed species are not considered here) species after approval of monazite-(Gd) and xenotime-(Gd).
The Gd analogue of lepersonnite-(Nd).
Not approved phases with species-defining gadolinium were identified in the The Moon regolith; there are also single finds from Kudriavy volcano, Russia (an oxide phase) and Kyauk Tha Mtn, Myanmar (Unnamed (Gd-dominant monazite)).
For more information about separation of Gd, Dy, and Sm from more abundant REEs see Unnamed (Possible Samarium Chloride) and Pavlovskoe REE-coal deposit site.
The Gd analogue of lepersonnite-(Nd).
Not approved phases with species-defining gadolinium were identified in the The Moon regolith; there are also single finds from Kudriavy volcano, Russia (an oxide phase) and Kyauk Tha Mtn, Myanmar (Unnamed (Gd-dominant monazite)).
For more information about separation of Gd, Dy, and Sm from more abundant REEs see Unnamed (Possible Samarium Chloride) and Pavlovskoe REE-coal deposit site.
Unique Identifiers
Mindat ID:
2378
Long-form identifier:
mindat:1:1:2378:4
Similar Names
| Lepersonnite-(Nd) | A valid IMA mineral species | Nd4(UO2)24(SiO4)4(CO3)8(OH)28 · 48H2O |
IMA Classification of Lepersonnite-(Gd)
Approved
IMA status notes:
Renamed by the IMA
IMA Formula:
[Ca0.5Gd0.5(H2O)18(OH)1.5][Gd(U6+O2)12(SiO3OH)2(CO3)4(OH)10O2(H2O)5]
Approval year:
1981
First published:
1982
Classification of Lepersonnite-(Gd)
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
17.1.12.1
17 : COMPOUND CARBONATES
1 : Miscellaneous
17 : COMPOUND CARBONATES
1 : Miscellaneous
17.4.12
17 : Silicates Containing other Anions
4 : Silicates with carbonates
17 : Silicates Containing other Anions
4 : Silicates with carbonates
Mineral Symbols
As of 2021 there are now IMAâCNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Lps-Gd | IMAâCNMNC | Warr, L.N. (2021). IMAâCNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of Lepersonnite-(Gd)
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Lepersonnite-(Gd)
Transparency:
Transparent, Translucent
Colour:
Bright yellow
Density:
3.97(5) g/cm3 (Measured) 3.8419 g/cm3 (Calculated)
Optical Data of Lepersonnite-(Gd)
Type:
Biaxial (-)
RI values:
nα = 1.638 nβ = 1.666 nγ = 1.682
2V:
Measured: 73° , Calculated: 72°
Max. Birefringence:
δ = 0.044
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 Âĩm 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 Âĩm 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:
Relatively weak.
Optical Extinction:
Y = c.
Pleochroism:
Visible
Comments:
X = pale yellow; Y = Z = bright yellow
Chemistry of Lepersonnite-(Gd)
Mindat Formula:
Ca(Gd,Dy)2(UO2)24(SiO4)4(CO3)8(OH)24 · 48H2O
Element Weights:
Crystallography of Lepersonnite-(Gd)
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pnnm
Setting:
Pnnm
Cell Parameters:
a = 11.850(7) Å, b = 16.16(2) Å, c = 39.506(17) Å
Ratio:
a:b:c = 0.733 : 1 : 2.445
Unit Cell V:
7,565.24 Ã
Âģ (Calculated from Unit Cell)
Z:
4
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.15 Ã | (100) |
| 3.65 Ã | (70) |
| 3.21 Ã | (50) |
| 2.86 Ã | (40) |
| 4.06 Ã | (15) |
| 11.1 Ã | (10) |
| 6.46 Ã | (10) |
Comments:
Shinkolobwe, Congo. Data 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 (Uâķâš) minerals] |
Type Occurrence of Lepersonnite-(Gd)
General Appearance of Type Material:
As mammilary crusts or spherules, to 5 mm in diameter, composed of radiating acicular crystals elongated along [001].
Place of Conservation of Type Material:
Royal Museum for Central Africa, Tervuren, Belgium, number RGM 13.781 (holotype).
National Museum for Natural History, Washington, D.C., USA, number 150.228 (type).
National Museum for Natural History, Washington, D.C., USA, number 150.228 (type).
Geological Setting of Type Material:
oxidation and hydration of uraninite
Associated Minerals at Type Locality:
Synonyms of Lepersonnite-(Gd)
Other Language Names for Lepersonnite-(Gd)
Dutch:Lepersonniet-(Gd)
German:Lepersonnit-(Gd)
Common Associates
Associations Based on Photo Data:
| 8 photos of Lepersonnite-(Gd) associated with Becquerelite | Ca(UO2)6O4(OH)6 · 8H2O |
| 6 photos of Lepersonnite-(Gd) associated with Studtite | [(UO2)(O2)(H2O)2] · H2O |
| 6 photos of Lepersonnite-(Gd) associated with Uraninite | UO2 |
| 5 photos of Lepersonnite-(Gd) associated with Curite | Pb3(H2O)2[(UO2)4O4(OH)3]2 |
| 3 photos of Lepersonnite-(Gd) associated with Bijvoetite-(Y) | Y8(UO2)16(CO3)16O8(OH)8 · 39H2O |
| 3 photos of Lepersonnite-(Gd) associated with Fourmarierite | Pb(UO2)4O3(OH)4 · 4H2O |
| 2 photos of Lepersonnite-(Gd) associated with 'Gummite' | |
| 2 photos of Lepersonnite-(Gd) associated with Uranophane | Ca(UO2)2(SiO3OH)2 · 5H2O |
Related Minerals - Strunz-mindat Grouping
| 5.EG.05 | SchrÃķckingerite | 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-(Nd) | Nd4(UO2)24(SiO4)4(CO3)8(OH)28 · 48H2O |
| 5.EG.15 | JeÅūekite | Na8[(UO2)(CO3)3](SO4)2 · 3H2O |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 63.7823% | 15,945,575 | Îą, Îē, Îģ |
| Thorium (Th) | 0.0000% | 0 | Îą, Îē, Îģ |
| Potassium (K) | 0.0000% | 0 | Îē, Îģ |
For comparison:
- Banana: ~15 Bq per fruit
- Granite: 1,000â3,000 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 ÂĩSv/year. Note that natural background radiation averages around 2400 ÂĩSv/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: â
| Distance | Dose rate | Risk |
|---|---|---|
| 1âŊcm | ||
| 10âŊcm | ||
| 1âŊm |
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-(Gd)
Not fluorescent.
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 Lepersonnite-(Gd)
mindat.org URL:
https://www.mindat.org/min-2378.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Lepersonnite-(Gd)
Reference List:
Dunn, P. J., Fleischer, M., Chao, G. Y., Cabri, L. J., Mandarino, J. A. (1983) New mineral names. American Mineralogist, 68 (11-12) 1248-1252
Localities for Lepersonnite-(Gd)
Showing 1 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
â - 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. (1982) +1 other reference |
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Shinkolobwe Mine, Shinkolobwe, Kambove Territory, Haut-Katanga, DR Congo