Editorial Feature

Arsenuranylite - Occurrence, Properties, and Distribution

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Oct 30 2014

Image Credit: Dlogger/Shutterstock.com

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	PE_{Arsenuranylite} = 1600.54 barns/electron U= PE_{Arsenuranylite} 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.