Leydetite
A valid IMA mineral species
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About Leydetite
Jean-Claude Leydet
Formula:
Fe(UO2)(SO4)2 · 11H2O
Colour:
Yellow to greenish
Lustre:
Vitreous
Hardness:
2
Specific Gravity:
2.55 (Calculated)
Crystal System:
Monoclinic
Name:
Honours Jean-Claude Leydet (born 18 April 1961 - died 21 November 2018), an amateur mineralogist from Brest (France), a great connoisseur of uranium minerals.
New structure type. Chemically related to deliensite.
Chemically very similar to rietveldite (a lower hydrate).
Isostructural with magnesioleydetite.
The structure is based on protasite anion topology; there is a sheet of UO7 bipyramids, that share four of their equatorial vertices with sulfate tetrahedra; thus, each tetrahedron has two vertices shared with UO7. The unshared equatorial vertices contain water molecules. The sheets are perpendicular to c. Fe ions and water molecules in the interlayer space link to the sheets via hydrogen bonds.
Chemically very similar to rietveldite (a lower hydrate).
Isostructural with magnesioleydetite.
The structure is based on protasite anion topology; there is a sheet of UO7 bipyramids, that share four of their equatorial vertices with sulfate tetrahedra; thus, each tetrahedron has two vertices shared with UO7. The unshared equatorial vertices contain water molecules. The sheets are perpendicular to c. Fe ions and water molecules in the interlayer space link to the sheets via hydrogen bonds.
Unique Identifiers
Mindat ID:
43586
Long-form identifier:
mindat:1:1:43586:8
IMA Classification of Leydetite
Classification of Leydetite
7.EB.15
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
E : Uranyl sulfates
B : With medium-sized cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
E : Uranyl sulfates
B : With medium-sized cations
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 |
|---|---|---|
| Ley | 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 Leydetite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Yellow to greenish
Streak:
Yellowish white
Hardness:
2 on Mohs scale
Cleavage:
Perfect
Perfect cleavage on (001).
Perfect cleavage on (001).
Density:
2.55 g/cm3 (Calculated)
Optical Data of Leydetite
Type:
Biaxial
RI values:
nα = 1.513(2) nβ = 1.522(2)
Surface Relief:
Unknown
Pleochroism:
Non-pleochroic
Comments:
Further optical properties could not be measured.
Chemistry of Leydetite
Mindat Formula:
Fe(UO2)(SO4)2 · 11H2O
Element Weights:
Common Impurities:
Mg
Crystallography of Leydetite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/m
Cell Parameters:
a = 11.3173 Å, b = 7.7258 Å, c = 21.8121 Å
β = 102.383°
β = 102.383°
Ratio:
a:b:c = 1.465 : 1 : 2.823
Unit Cell V:
1,862.78 ų (Calculated from Unit Cell)
Z:
4
Comment:
C2/c
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 10.625 Å | (100) |
| 6.277 Å | (1) |
| 5.321 Å | (66) |
| 3.549 Å | (5) |
| 2.663 Å | (4) |
| 2.131 Å | (2) |
Comments:
From 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] | |
| 47b : [Sulfates and sulfites] | |
| 47f : [Uranyl (U⁶⁺) minerals] |
Type Occurrence of Leydetite
General Appearance of Type Material:
Tabular crystals up to 2 mm.
Place of Conservation of Type Material:
Musée Cantonal de Géologie, Lausanne, Switzerland, registration number MGL 92661.
Geological Setting of Type Material:
Supergene alteration of a uranium deposit in sandstones, pelites and conglomerates.
Associated Minerals at Type Locality:
Synonyms of Leydetite
Other Language Names for Leydetite
Common Associates
Related Minerals - Strunz-mindat Grouping
| 7.EB. | Bobcookite | NaAl(UO2)2(SO4)4 · 18H2O |
| 7.EB. | Zincorietveldite | Zn(UO2)(SO4)2(H2O)5 |
| 7.EB. | Chenowethite | Mg(H2O)6[(UO2)2(SO4)2(OH)2] · 5H2O |
| 7.EB.I | Shinarumpite | [Co(H2O)6][(UO2)(SO4)2(H2O)] · 4H2O |
| 7.EB. | Alwilkinsite-(Y) | Y(UO2)3(SO4)2O(OH)3(H2O)7 · 7H2O |
| 7.EB. | Gurzhiite | Al(UO2)(SO4)2F · 10H2O |
| 7.EB.05 | Johannite | Cu(UO2)2(SO4)2(OH)2 · 8H2O |
| 7.EB.05 | Meitnerite | (NH4)(UO2)(SO4)(OH) · 2H2O |
| 7.EB.10 | Rietveldite | Fe(UO2)(SO4)2(H2O)5 |
| 7.EB.10 | Deliensite | Fe[(UO2)2(SO4)2(OH)2](H2O)7 |
| 7.EB.15 | Strassmannite | Al(UO2)(SO4)2F · 16H2O |
| 7.EB.15 | Magnesioleydetite | Mg(UO2)(SO4)2 · 11H2O |
| 7.EB.20 | Greenlizardite | (NH4)Na(UO2)2(SO4)2(OH)2 · 4H2O |
| 7.EB.25 | Markcooperite | Pb2(UO2)(TeO6) |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 33.2366% | 8,309,150 | 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 Leydetite
Not fluorescent.
Other Information
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 Leydetite
mindat.org URL:
https://www.mindat.org/min-43586.html
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References for Leydetite
Reference List:
Plášil, J., Hauser, J., Petříček, V., Meisser, N., Mills, S. J., Škoda, R., Fejfarová, K., Čejka, J., Sejkora, J., Hloušek, J., Johannet, J.-M., Machovič, V., Lapčák, L. (2012) Crystal structure and formula revision of deliensite, Fe[(UO2)2(SO4)2(OH)2](H2O)7. Mineralogical Magazine, 76 (7) 2837-2860 doi:10.1180/minmag.2012.076.7.14 [as unnamed phase]
Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2013) IMA Commission on New Minerals, Nomenclature and Classification. CNMNC Newsletter No. 15. Mineralogical Magazine, 77 (1) 1-12 doi:10.1180/minmag.2013.077.1.01
Plášil, J., Kasatkin, A. V., Škoda, R., Novák, M., Kallistová, A., Dušek, M., Skála, R., Fejfarová, K., Čejka, J., Meisser, N., Goethals, H., Machovič, V., Lapčák, L. (2013) Leydetite, Fe(UO2)(SO4)2(H2O)11, a new uranyl sulfate mineral from Mas d’Alary, Lodève, France. Mineralogical Magazine, 77 (4) 429-441 doi:10.1180/minmag.2013.077.4.03
Localities for Leydetite
Showing 3 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.
France (TL) | |
| Williams et al. (2013) +1 other reference |
| Plášil et al. (2012) +1 other reference |
USA | |
| Kampf et al. (2018) |
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Mas d'Alary opencast mine, Lodève, Lodève, Hérault, Occitanie, France