Fermiite
A valid IMA mineral species
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About Fermiite
Dr. Enrico Fermi
Formula:
Na4(UO2)(SO4)3 · 3H2O
Colour:
Pale greenish-yellow
Lustre:
Vitreous
Hardness:
2½
Specific Gravity:
3.23
Crystal System:
Orthorhombic
Name:
Named by A.R. Kampf, J. Plášil, A.V. Kasatkin, J. Marty, and J. Čejka in 2015 in honor of Dr. Enrico Fermi (29 September 1901, Rome, Italy - 28 November 1954, Chicago, Illinois, USA), Italian-American theoretical and experimental physicist. He made significant contributions to quantum theory, nuclear and particle physics, and statistical mechanics. He was awarded the 1938 Nobel Prize in Physics.
Structurally related to meisserite. Also structurally somewhat similar to oppenheimerite.
Chemically related to oppenheimerite, klaprothite, péligotite, ottohahnite; plášilite and natrozippeite (basic salts); belakovskiite and meisserite (sulfate-hydrosulfates).
As typical for uranyl sulfates, U polyhedra are square pentagonal bipyramids, with U atoms surrounded by 7 O atoms (two apical bonds of the bipyramid constitute the uranyl group). There are infinite chains formed by linking the adjacent bipyramids by two bridging sulfate groups. In fermiite the chain of [(UO2)(SO4)3]4– composition is parallel to [100]. The chains are linked through 5 different Na–O polyhedra.
Chemically related to oppenheimerite, klaprothite, péligotite, ottohahnite; plášilite and natrozippeite (basic salts); belakovskiite and meisserite (sulfate-hydrosulfates).
As typical for uranyl sulfates, U polyhedra are square pentagonal bipyramids, with U atoms surrounded by 7 O atoms (two apical bonds of the bipyramid constitute the uranyl group). There are infinite chains formed by linking the adjacent bipyramids by two bridging sulfate groups. In fermiite the chain of [(UO2)(SO4)3]4– composition is parallel to [100]. The chains are linked through 5 different Na–O polyhedra.
Unique Identifiers
Mindat ID:
46506
Long-form identifier:
mindat:1:1:46506:3
IMA Classification of Fermiite
Classification of Fermiite
7.EC.45
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
E : Uranyl sulfates
C : With medium-sized and large cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
E : Uranyl sulfates
C : With medium-sized and large 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 |
|---|---|---|
| Fmi | 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 Fermiite
Vitreous
Transparency:
Transparent
Colour:
Pale greenish-yellow
Streak:
White
Hardness:
2½ on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
no cleavage
no cleavage
Fracture:
Conchoidal
Density:
3.23 g/cm3 (Measured) 3.313 g/cm3 (Calculated)
Optical Data of Fermiite
Type:
Biaxial (+)
RI values:
nα = 1.527(1) nβ = 1.534(1) nγ = 1.567(1)
2V:
Measured: 51° , Calculated: 50°
Max. Birefringence:
δ = 0.040
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:
None to Very Low
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:
r < v, distinct.
Pleochroism:
Visible
Comments:
X, Y = colourless, Z = pale greenish yellow; X = Y < Z
Chemistry of Fermiite
Mindat Formula:
Na4(UO2)(SO4)3 · 3H2O
Element Weights:
Crystallography of Fermiite
Crystal System:
Orthorhombic
Class (H-M):
mm2 - Pyramidal
Space Group:
Pmn21
Setting:
Pmn21
Cell Parameters:
a = 11.8407(12) Å, b = 7.8695(5) Å, c = 15.3255(19) Å
Ratio:
a:b:c = 1.505 : 1 : 1.947
Unit Cell V:
1428 ų
Z:
4
Morphology:
Prisms
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.71 Å | (43) |
| 7.01 Å | (100) |
| 6.00 Å | (49) |
| 4.70 Å | (42) |
| 3.476 Å | (85) |
| 3.336 Å | (55) |
| 3.131 Å | (57) |
| 2.762 Å | (46) |
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] | |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 55 : Anthropogenic mine minerals |
Geological Setting:
"Common Associated Minerals" = general assemblage at the TL
Type Occurrence of Fermiite
General Appearance of Type Material:
prisms with {101} face habit, up to ~0.5 mm long; in subparallel or irregular aggregates. Other forms reported: {011}, {110}, {010}, {001}
Place of Conservation of Type Material:
Cotype material is deposited in the collections of the Natural History Museum of Los Angeles County 900 Exposition Boulevard, Los Angeles, California 90007, USA, catalogue numbers 65546, 65547 and 65548, and the Fersman Mineralogical Museum of the Russian
Geological Setting of Type Material:
As a secondary alteration phase
Associated Minerals at Type Locality:
Synonyms of Fermiite
Other Language Names for Fermiite
Related Minerals - Strunz-mindat Grouping
| 7.EC. | Nitscheite | (NH4)2[(UO2)2(SO4)3(H2O)2] · 3H2O |
| 7.EC. | Beshtauite | (NH4)2(UO2)(SO4)2 · 2H2O |
| 7.EC. | Oldsite-(K) | K2Fe2+[(UO2)(SO4)2]2(H2O)8 |
| 7.EC. | Adolfpateraite | K(UO2)(SO4)(OH)(H2O) |
| 7.EC. | Libbyite | (NH4)2(Na2◻)[(UO2)2(SO4)3(H2O)]2 · 7H2O |
| 7.EC. | Seaborgite | LiK2Na6(UO2)(SO4)5(SO3OH)(H2O) |
| 7.EC.05 | Zinczippeite | Zn(UO2)2(SO4)O2 · 3.5H2O |
| 7.EC.05 | Zippeite | K3(UO2)4(SO4)2O3(OH) · 3H2O |
| 7.EC.05 | Cobaltzippeite | Co(UO2)2(SO4)O2 · 3.5H2O |
| 7.EC.05 | Nickelzippeite | Ni2(UO2)6(SO4)3(OH)10 · 16H2O |
| 7.EC.05 | Redcanyonite | (NH4)2Mn[(UO2)4O4(SO4)2](H2O)4 |
| 7.EC.05 | Natrozippeite | Na5(UO2)8(SO4)4O5(OH)3 · 12H2O |
| 7.EC.05 | Magnesiozippeite | Mg(UO2)2(SO4)O2 · 3.5H2O |
| 7.EC.05 | Ammoniozippeite | (NH4)2[(UO2)2(SO4)O2] · H2O |
| 7.EC.05 | Plavnoite | K0.8Mn0.6[(UO2)2O2(SO4)] · 3.5H2O |
| 7.EC.10 | Rabejacite | Ca(UO2)4(SO4)2(OH)6 · 6H2O |
| 7.EC.10 | Svornostite-(NH4) | (NH4)2Mg(UO2)2(SO4)4(H2O)8 |
| 7.EC.10 | Svornostite-(K) | K2Mg[(UO2)(SO4)2]2(H2O)8 |
| 7.EC.15 | Sejkoraite-(Y) | Y2(UO2)8(SO4)4O6(OH)2 · 26H2O |
| 7.EC.15 | Marécottite | Mg3(UO2)8(SO4)4O6(OH)2 · 28H2O |
| 7.EC.15 | Hubbardite | Mg(H2O)6[(UO2)2O(OH)(SO4)]2 · 8H2O |
| 7.EC.20 | Pseudojohannite | Cu3(UO2)4(SO4)2O4(OH)2 · 12H2O |
| 7.EC.40 | Bluelizardite | Na7(UO2)(SO4)4Cl(H2O)2 |
| 7.EC.45 | Meisserite | Na5(UO2)(SO4)3(SO3OH)(H2O) |
| 7.EC.45 | Oppenheimerite | Na2(UO2)(SO4)2 · 3H2O |
| 7.EC.50 | Feynmanite | Na(UO2)(SO4)(OH) · 3.5H2O |
| 7.EC.50 | Plášilite | Na(UO2)(SO4)(OH) · 2H2O |
| 7.EC.55 | Geschieberite | K2(UO2)(SO4)2 · 2H2O |
| 7.EC.60 | Ottohahnite | Na6(UO2)2(SO4)5(H2O)7 · 1.5H2O |
| 7.EC.65 | Péligotite | Na6(UO2)(SO4)4 · 4H2O |
| 7.EC.70 | Klaprothite | Na6(UO2)(SO4)4 · 4H2O |
| 7.EC.75 | Lussierite | Na10[(UO2)(SO4)4](SO4)2 · 3(H2O) |
| 7.EC.80 | Navrotskyite | K2Na10(UO2)3(SO4)9 · 2H2O |
| 7.EC.85 | Pseudomeisserite-(NH4) | (NH4)2Na4[(UO2)2(SO4)5] · 4H2O |
| 7.EC.90 | Wetherillite | Na2Mg(UO2)2(SO4)4 · 18H2O |
Radioactivity
Radioactivity:
| Element | % Content | Activity (Bq/kg) | Radiation Type |
|---|---|---|---|
| Uranium (U) | 33.8003% | 8,450,075 | 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 Fermiite
Bright greenishwhite fluorescence
Other Information
Notes:
Easily soluble in RT H2O; Raman bands [cm-1]: 3540, 3465, 3285; (O–H stretching); 1606w (water bending); weak with shoulders: 1228, 1180, 1120, 1104, 1080 [ν3 sulfate groups antisymmetric stretching]; 1013s + 996s [ν1 sulfate groups symmetric stretching]; 922w [ν3 uranyl groups antisymmetric stretching]; 830vs with 860sh and 813sh [ν1 uranyl groups symmetric stretching]; 638w, 616w, 583w [ν4(δ) sulfate groups]; 506, 443, 384 [ν2(δ) sulfate bending]; 207 [ν2(δ) uranyl groups]; below 200 (lattice vibrations)
Health Risks:
Radioactive
Internet Links for Fermiite
mindat.org URL:
https://www.mindat.org/min-46506.html
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References for Fermiite
Reference List:
Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2015) New minerals and nomenclature modifications approved in 2014 and 2015. Newsletter No 23. Mineralogical Magazine, 79 (1) 51-58 doi:10.1180/minmag.2015.079.1.05
Kampf, Anthony R., Plášil, Jakub, Kasatkin, Anatoly V., Marty, Joe, Čejka, Jiří (2015) Fermiite, Na4(UO2)(SO4)3·3H2O and oppenheimerite, Na2(UO2)(SO4)2·3H2O, two new uranyl sulfate minerals from the Blue Lizard mine, San Juan County, Utah, USA. Mineralogical Magazine, 79 (5) 1123-1142 doi:10.1180/minmag.2015.079.5.8
Localities for Fermiite
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.
USA (TL) | |
| Williams et al. (2015) +2 other references |
| Kampf et al. (2018) |
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Blue Lizard Mine, Red Canyon Mining District, San Juan County, Utah, USA