Cuprosklodowskite

Cuprosklodowskite is a secondary uranium mineral formed by alteration of earlier uranium minerals. Its empirical formula is Cu(UO₂)₂(HSiO₄)₂·6(H₂O).^[3] Cuprosklodowskite is a nesosilicate mineral, It is grass green to dark green in color, and its crystal habit is typically acicular, flat bladed crystals. It is a strongly radioactive mineral.

Cuprosklodowskite
Cuprosklodowskite, Musonoi mine, Kolwezi, Lualaba District, Democratic Republic of the Congo {3.6 x 2.7 x 2.2 cm}
General
Category	Uranium mineral
Formula	Cu(UO2)2(HSiO4)2·6(H2O)
IMA symbol	Cskl[1]
Strunz classification	9.AK.10
Crystal system	Triclinic
Crystal class	Pinacoidal (1) (same H-M symbol)
Space group	P1
Unit cell	a = 7.052(5) Å, b = 9.267(8) Å, c = 6.655(5) Å; α = 109.23°, β = 89.84°, γ = 110.01°; Z = 1
Identification
Color	Yellowish to grass-green
Crystal habit	In radiating groups of acicular flattened or bladed needles or fibrous crusts
Twinning	Twice a year
Cleavage	On {100}
Fracture	Uneven
Mohs scale hardness	4
Luster	Dull to silky in aggregates
Streak	Greenish yellow
Diaphaneity	Transparent to translucent
Specific gravity	3.85
Optical properties	Biaxial (-)
Refractive index	nα = 1.654 - 1.655 nβ = 1.664 - 1.667 nγ = 1.664 - 1.667
Birefringence	δ = 0.010 - 0.012
Pleochroism	X = nearly colorless; Y = Z = yellowish green
Other characteristics	Radioactive
References	[2][3][4]

Cuprosklodowskite was discovered in 1933 at the Kalongwe deposit in (then) Katanga province, Belgian Congo, the type locality. It was named in the mistaken belief that the mineral was the copper analogue of sklodowskite, which in turn was named for Marie Skłodowska Curie (1867–1934).

It occurs in association with becquerelite, brochantite, uranophane, kasolite, vandenbrandeite, liebigite and compreignacite.^[2][5]