Fermiite

Fermiite is a rare uranium mineral with the formula Na4(UO2)(SO4)3·3H2O.[3] Chemically related minerals include oppenheimerite, meisserite (which is also structurally-related to fermiite),[2] belakovskiite, natrozippeite and plášilite.[4][5][6][7][8] Fermiite comes from the Blue Lizard mine, San Juan County, Utah, USA, which is known for many rare uranium minerals.[1][2][9] The name honors Enrico Fermi (1901–1954).[2]

Fermiite
General
CategorySulfate mineral
Formula
(repeating unit)		Na4(UO2)(SO4)3·3H2O
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[1][2]

Association

Fermiite is closely associated with numerous other sulfate minerals: oppenheimerite, bluelizardite, wetherillite, blödite, manganoblödite, chalcanthite, epsomite, gypsum, hexahydrite, kröhnkite, sideronatrite and tamarugite.[3]

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.[3]

References
  1. 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
  2. "Fermiite: Fermiite mineral information and data". Mindat.org. Retrieved 2016-03-04.
  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
  4. "Oppenheimerite: Oppenheimerite mineral information and data". Mindat.org. Retrieved 2016-03-10.
  5. "Meisserite: Meisserite mineral information and data". Mindat.org. Retrieved 2016-03-10.
  6. "Belakovskiite: Belakovskiite mineral information and data". Mindat.org. Retrieved 2016-03-10.
  7. "Natrozippeite: Natrozippeite mineral information and data". Mindat.org. Retrieved 2016-03-10.
  8. "Plášilite: Plášilite mineral information and data". Mindat.org. Retrieved 2016-03-10.
  9. "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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