Fermiite

Fermiite
General
Category Sulfate mineral
Formula
(repeating unit)		 Na4(UO2)(SO4)3·3H2O
Crystal system Orthorhombic, Pmn21
Unit cell a=11.84, b=7.87, c=15.33 [Å], (approximated)
Identification
Color Pale greenish-yellow
Crystal habit prismatic
Crystal symmetry Orthorhombic - Pyramidal (mm2)
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)
References [1][2]

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]

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. 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
  2. 1 2 3 4 "Fermiite: Fermiite mineral information and data". Mindat.org. Retrieved 2016-03-04.
  3. 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
  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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