Zeunerite

Zeunerite is a green copper uranium arsenate mineral with formula Cu(UO₂)₂(AsO₄)₂•(10-16)H₂O. It is a member of the autunite group. The associated mineral metazeunerite is a dehydration product of zeunerite.

Zeunerite
General
Category	Arsenate mineral
Formula (repeating unit)	Cu(UO2)2(AsO4)2•(10-16)H2O
Strunz classification	8.EB.05
Dana classification	40.02a.14.01
Crystal system	Tetragonal
Crystal class	Ditetragonal dipyramidal (4/mmm) H-M symbol: (4/m 2/m 2/m)
Space group	P4/nnc
Identification
Color	Yellow-green, emerald-green
Crystal habit	Crystals flat tabular on {001}, commonly subparallel to micaceous
Cleavage	{001} perfect, {100}, distinct
Mohs scale hardness	2.5
Luster	Vitreous
Streak	pale green
Diaphaneity	Transparent, becoming translucent on dehydration
Specific gravity	3.2 - 3.4
Optical properties	Uniaxial (-)
Refractive index	nω = 1.610 - 1.613 nε = 1.582 - 1.585
Birefringence	δ = 0.028
Pleochroism	Visible
Other characteristics	Radioactive
References	[1][2][3]

Zeunerite occurs as a secondary mineral in the oxidized weathering zone of hydrothermal uranium ore deposits which contain arsenic. Olivenite, mansfieldite, scorodite, azurite and malachite are found in association with zeunerite.[1]

It was first described in 1872 for an occurrence in the Schneeberg District, Erzgebirge, Saxony, Germany. It was named for Gustav Anton Zeuner (1828–1907).[2]