Fermiite
General
CategorySulfate mineral
Formula
(repeating unit)		Na4(UO2)(SO4)3·3H2O
IMA symbolFmi[1]
Crystal systemOrthorhombic
Crystal classPyramidal (mm2)
H-M symbol: (mm2)
Space groupPmn21
Unit cella = 11.84, b = 7.87
c = 15.33 [Å] (approximated); Z = 4
Identification
ColorPale greenish-yellow
Crystal habitprismatic
CleavageNone
TenacityBrittle
Mohs scale hardness2.5
StreakWhite
DiaphaneityTransparent
Density3.31 (calculated); 3.23 (measured)
Optical propertiesBiaxal (+)
Refractive indexnα=1.52, nβ=1.53, nγ=1.57 (approximated)
PleochroismColourless (X & Y), pale greenish-yellow (Z)
2V angle50o (calculated)
Other characteristics Radioactive
References[2][3]

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.[5][6][7][8][9] Fermiite comes from the Blue Lizard mine, San Juan County, Utah, USA, which is known for many rare uranium minerals.[2][3][10] 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

  1. ↑ 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.
  2. 1 2 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
  3. 1 2 3 4 "Fermiite: Fermiite mineral information and data". Mindat.org. Retrieved 2016-03-04.
  4. 1 2 3 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
  5. ↑ "Oppenheimerite: Oppenheimerite mineral information and data". Mindat.org. Retrieved 2016-03-10.
  6. ↑ "Meisserite: Meisserite mineral information and data". Mindat.org. Retrieved 2016-03-10.
  7. ↑ "Belakovskiite: Belakovskiite mineral information and data". Mindat.org. Retrieved 2016-03-10.
  8. ↑ "Natrozippeite: Natrozippeite mineral information and data". Mindat.org. Retrieved 2016-03-10.
  9. ↑ "Plášilite: Plášilite mineral information and data". Mindat.org. Retrieved 2016-03-10.
  10. ↑ "Blue Lizard Mine, Chocolate Drop, Red Canyon, White Canyon District, San Juan Co., Utah, USA - Mindat.org". Mindat.org. Retrieved 2016-03-04.


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