Arsenuranylite - Occurrence, Properties, and Distribution

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Article updated on 6 March 2020 by Kerry Taylor-Smith

Chemical Formula – Ca(UO2)4(AsO4)2(OH)4•6(H2O)

Arsenuranylite is an orthorhombic-dipyramidal mineral containing uranium, oxygen, hydrogen, calcium, and arsenic. The mineral was discovered in Russia in 1958. It was named for arsenic and uranium in its composition and its relation to phosphuranylite.

Properties of Arsenuranylite

The following are the key properties of Arsenuranylite:

Cell Data

  • Space Group: Bmmb
  • a = 15.40
  • b = 17.40
  • c = 13.768
  • Z = 6

Crystal Data

  • Orthorhombic
  • Point Group: 2/m 2/m 2/m.
  • As fine scales and lichenlike incrustations of elongated crystals, to 0.5 mm
  • X-ray Powder Pattern: 7.72 (10), 3.85 (10), 8.41 (8), 3.13 (8), 3.42 (7), 1.778 (7), 1.729 (7)

Chemical Composition

Elements Content 1 Content 2
UO3 68.64 72.68
As2O5 16.68 14.6
H2O 9.15 9.16
CaO 3.48 3.56
Total 97.95 100

 

Content 1: Cherkasar deposit, Uzbekistan; corresponding to Ca1.00(UO2)3.89(AsO4)2.34 • 8.10H2O.

Content 2: Ca(UO2)4(AsO4)2(OH)4 • 6H2O.

Optical Properties

  • Optical Class: Biaxial (–)
  • α = 1.737
  • β = 1.761
  • γ = 1.771–1.778
  • 2V(meas.) = n.d.

Estimated Properties

. .
Electron density Bulk density (electron density)=3.66 g/cm3
note: Specific gravity of Arsenuranylite =4.25 g/cm3
Photoelectric PEArsenuranylite = 1600.54 barns/electron
U= PEArsenuranylite x ρ Electron density= 5859.62 barns/cm3
Fermion index Fermion index = 0.004
Boson index = 0.99
Radioactivity Arsenuranylite is radioactive

 

How to Identify Arsenuranylite

Arsenuranylite is a yellow- or orange-colored mineral with a light yellow streak and translucent appearance. It exhibits a scaly structure - much like fish scales - and perfect cleavage. The average density of arsenuranylite is 4.25 g/cm3, and its hardness is 2.5 on the Mohs scale of mineral hardness.

Global Distribution

Arsenuranylite is distributed in the following places:

  • Cherkasar uranium deposit, 30 km northwest of Pap, Chatkal Range, Uzbekistan
  • Menzenschwand, Black Forest. Germany.

Occurrence of Arsenuranylite and Useful Mineral Association

Arsenuranylite occurs in the oxidized zone of a uranium deposit containing arsenic-bearing sulfides. The mineral is closely associated with uranospinite, novacekite, metazeunerite, schoepite, and paraschoepite.

References and Further Reading

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