Alwilkinsite-(Y)
A valid IMA mineral species
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About Alwilkinsite-(Y)
Al Wilkins
Formula:
Y(UO2)3(SO4)2O(OH)3(H2O)7 · 7H2O
Colour:
Yellowish-green; lemon yellow
Hardness:
2 - 2½
Specific Gravity:
3.371 (Calculated)
Crystal System:
Orthorhombic
Name:
In honour of Alan (Al) J. Wilkins, MD (born 1955), who discovered of the mineral
New structure type.
Chemically related to sejkoraite-(Y), which is the second yttrium-uranyl sulfate mineral currently known. Other Y-UO2 minerals: bijvoetite-(Y), kamotoite-(Y) (carbonates). These three minerals and alwilkinsite-(Y) constitute the whole small group of natural Y-U salts (however, Y-U oxide minerals are also known). One of a few Y-rich sulphate minerals.
The structure is based on edge-sharing chains of uranyl bipyramids, and the sulfate tetrahedra are located outside them. In terms of chain linkage the mineral is close to zippeite. The uranyl-sulfate chains of the mineral are somewhat similar to the corresponding features in uranopilite.
Chemically related to sejkoraite-(Y), which is the second yttrium-uranyl sulfate mineral currently known. Other Y-UO2 minerals: bijvoetite-(Y), kamotoite-(Y) (carbonates). These three minerals and alwilkinsite-(Y) constitute the whole small group of natural Y-U salts (however, Y-U oxide minerals are also known). One of a few Y-rich sulphate minerals.
The structure is based on edge-sharing chains of uranyl bipyramids, and the sulfate tetrahedra are located outside them. In terms of chain linkage the mineral is close to zippeite. The uranyl-sulfate chains of the mineral are somewhat similar to the corresponding features in uranopilite.
Unique Identifiers
Mindat ID:
47025
Long-form identifier:
mindat:1:1:47025:0
IMA Classification of Alwilkinsite-(Y)
Approved
IMA Formula:
Y(U6+O2)3(S6+O4)2O(OH)3(H2O)7·7H2O
Approval year:
2016
First published:
2017
Type description reference:
Classification of Alwilkinsite-(Y)
7.EB.
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 |
|---|---|---|
| Alw-Y | 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 Alwilkinsite-(Y)
Colour:
Yellowish-green; lemon yellow
Hardness:
2 - 2½ on Mohs scale
Comment:
ca. 2-2.5
Tenacity:
Brittle
Cleavage:
Perfect
on [010]
on [010]
Parting:
Slightly flexible before brittle
Fracture:
Splintery
Comment:
Slightly flexible before brittle failure with splintery fracture and perfect cleavage
Density:
3.371 g/cm3 (Calculated)
Optical Data of Alwilkinsite-(Y)
Type:
Biaxial (+)
RI values:
nα = 1.573(1) nβ = 1.581(1) nγ = 1.601(1)
2V:
Measured: 65.3° (1)
Max. Birefringence:
δ = 0.028
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 (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 (r < v)
Pleochroism:
Non-pleochroic
Comments:
Optical orientation: X = c, Y = a, Z = b
Chemistry of Alwilkinsite-(Y)
Mindat Formula:
Y(UO2)3(SO4)2O(OH)3(H2O)7 · 7H2O
Element Weights:
Crystallography of Alwilkinsite-(Y)
Crystal System:
Orthorhombic
Class (H-M):
222 - Disphenoidal
Space Group:
P212121
Setting:
P212121
Cell Parameters:
a = 11.6194(5) Å, b = 12.4250(6) Å, c = 19.4495(14) Å
Ratio:
a:b:c = 0.935 : 1 : 1.565
Unit Cell V:
2807.9 ų
Z:
4
Morphology:
Acicular crystals, needles, elongate on [010], with domatic terminations and exhibits the forms {102}, {301} and {12-4}.
Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| M11987 | Alwilkinsite-(Y) | Kampf, Anthony R., Plášil, Jakub, Cejka, Jirí, Marty, Joe, Škoda, Radek, Lapcák, Ladislav (2017) Alwilkinsite-(Y) Alwilkinsite-(Y), a new rare-earth uranyl sulfate mineral from the Blue Lizard mine, San Juan County, Utah, USA. Mineralogical Magazine, 81 (4) 895-907 doi:10.1180/minmag.2016.080.139 |  | 2017 | Blue Lizard Mine, Utah, USA | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 9.88 Å | (100) |
| 7.47 Å | (13) |
| 5.621 Å | (17) |
| 4.483 Å | (18) |
| 3.886 Å | (14) |
| 3.322 Å | (46) |
| 3.223 Å | (13) |
| 3.145 Å | (16) |
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] | |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 55 : Anthropogenic mine minerals |
Type Occurrence of Alwilkinsite-(Y)
General Appearance of Type Material:
Needle-like crystals, elongation on [010]; domatic terminations present; observed forms: {102}, {301} and {12_4}
Place of Conservation of Type Material:
Mineralogical collections of the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA (catalogue number 65629)
Empirical Formula of Type Material:
(Y0.66Dy0.08Gd0.06Er0.05Nd0.03Yb0.03Sm0.02Ce0.01)?0.94(H2O)7[(UO2)3(S1.01O4)2O(OH)3]·7H2O
Geological Setting of Type Material:
Secondary alteration phase
Synonyms of Alwilkinsite-(Y)
Other Language Names for Alwilkinsite-(Y)
Common Associates
Associations Based on Photo Data:
| 8 photos of Alwilkinsite-(Y) associated with Gypsum | CaSO4 · 2H2O |
| 3 photos of Alwilkinsite-(Y) associated with Zippeite | K3(UO2)4(SO4)2O3(OH) · 3H2O |
| 3 photos of Alwilkinsite-(Y) associated with Redcanyonite | (NH4)2Mn[(UO2)4O4(SO4)2](H2O)4 |
| 2 photos of Alwilkinsite-(Y) associated with Devilline | CaCu4(SO4)2(OH)6 · 3H2O |
| 1 photo of Alwilkinsite-(Y) associated with Johannite | Cu(UO2)2(SO4)2(OH)2 · 8H2O |
| 1 photo of Alwilkinsite-(Y) associated with Malachite | Cu2(CO3)(OH)2 |
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. | 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 | Leydetite | Fe(UO2)(SO4)2 · 11H2O |
| 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) | 50.6319% | 12,657,975 | 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 Alwilkinsite-(Y)
Dull greenish-gray fluorescence
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 Alwilkinsite-(Y)
mindat.org URL:
https://www.mindat.org/min-47025.html
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References for Alwilkinsite-(Y)
Localities for Alwilkinsite-(Y)
Showing 2 localities.
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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.
Italy | |
| Campostrini (2017) |
USA (TL) | |
| Hålenius et al. (2016) +1 other reference |
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Val Daone Mine, Limes, Daone Valley, Daone, Valdaone, Trento Province, Trentino-Alto Adige/Südtirol, Italy