| Fermiite | |
|---|---|
| General | |
| Category | Sulfate mineral |
| Formula | Na4(UO2)(SO4)3·3H2O |
| IMA symbol | Fmi1 |
| Crystal system | Orthorhombic |
| Crystal class | Pyramidal (mm2) H-M symbol: (mm2) |
| Space group | Pmn21 |
| Unit cell | a = 11.84, b = 7.87 c = 15.33 [Å] (approximated); Z = 4 |
| Identification | |
| Color | Pale greenish-yellow |
| Crystal habit | prismatic |
| Cleavage | None |
| Tenacity | Brittle |
| Mohs scale hardness | 2.5 |
| Streak | White |
| Diaphaneity | Transparent |
| Density | 3.31 (calculated); 3.23 (measured) |
| Optical properties | Biaxal (+) |
| Refractive index | nα=1.52, nβ=1.53, nγ=1.57 (approximated) |
| Pleochroism | Colourless (X & Y), pale greenish-yellow (Z) |
| 2V angle | 50o (calculated) |
| Other characteristics |  Radioactive |
| References | 23 |
Fermiite is a rare uranium mineral with the formula Na4(UO2)(SO4)3·3H2O.4 Chemically related minerals include oppenheimerite, meisserite (which is also structurally-related to fermiite),3 belakovskiite, natrozippeite and plášilite.56789 Fermiite comes from the Blue Lizard mine, San Juan County, Utah, USA, which is known for many rare uranium minerals.2310 The name honors Enrico Fermi (1901–1954).3
Association
Fermiite is closely associated with numerous other sulfate minerals: oppenheimerite, bluelizardite, wetherillite, blödite, manganoblödite, chalcanthite, epsomite, gypsum, hexahydrite, kröhnkite, sideronatrite and tamarugite.4
Crystal structure
The main building block of the crystal structure of fermiite is a chain of the composition (UO2)(SO4)3. Chains are connected with five types of Na-O polyhedra.4
References
References
- Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- Kampf, A.R., Plášil, J., Kasatkin, A.V., Marty, J., and Čejka, J., 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
- "Fermiite: Fermiite mineral information and data". Mindat.org. Retrieved 2016-03-04.
- Kampf, A.R., Plášil, J., Kasatkin, A.V., Marty, J., and Čejka, J., 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
- "Oppenheimerite: Oppenheimerite mineral information and data". Mindat.org. Retrieved 2016-03-10.
- "Meisserite: Meisserite mineral information and data". Mindat.org. Retrieved 2016-03-10.
- "Belakovskiite: Belakovskiite mineral information and data". Mindat.org. Retrieved 2016-03-10.
- "Natrozippeite: Natrozippeite mineral information and data". Mindat.org. Retrieved 2016-03-10.
- "Plášilite: Plášilite mineral information and data". Mindat.org. Retrieved 2016-03-10.
- "Blue Lizard Mine, Chocolate Drop, Red Canyon, White Canyon District, San Juan Co., Utah, USA - Mindat.org". Mindat.org. Retrieved 2016-03-04.