Vandenbrandeite

Vandenbrandeite is a mineral named after a Belgian geologist, Pierre Van den Brande, who discovered an ore deposit. It was named in 1932, and has been a valid mineral ever since then.^[2]

Vandenbrandeite
General
Category	Minerals
Formula	Cu(UO2)(OH)4
IMA symbol	Vbd[1]
Strunz classification	04.GB.45
Dana classification	05.03.02.01
Crystal system	Triclinic
Crystal class	Triclinic-Pinacoidal
Space group	P1
Unit cell	254.99 ų
Identification
Color	Blackish green to dark green with bluish green tint
Cleavage	Perfect on {001}, {110} Distinct and also indisctinct in the [001] zone
Fracture	None
Tenacity	Brittle
Mohs scale hardness	4
Luster	Vitreous, sub-vitreous, greasy
Streak	Green
Diaphaneity	Transparent, translucent
Specific gravity	5.03
Density	5.03
Optical properties	Biaxial (-)
Refractive index	nα = 1.765 - 1.770 nβ = 1.780 - 1.792 nγ = 1.800
Birefringence	0.035
Pleochroism	Visible
2V angle	Measured 90° Calculated 60°- 88°
Dispersion	Visible to strong
Ultraviolet fluorescence	None
Other characteristics	Radioactive

Properties

Vandenbrandeite grows in microcrystals, up to half a millimeter. It may be rounded or lathlike. The crystals are flattened on {001}. It grows in parallel aggregates, in a lamellar, scaly shape.^[3] It is tabular, meaning its dimensions in one direction are weak.^[4] It is a pleochroic mineral. Depending on the axis the mineral is seen, the color of it changes, which is an optical phenomenon. It appears blue-green on the x-axis and yellow-green on the z-axis. It is highly stable in the presence of both water and hydrogen peroxide.^[2] Vandenbrandeite, due to being strongly radioactive, is usually closely associated with other radioactive minerals.^[5] Its radioactive properties are due to its composition. The mineral is made out of 59.27% uranium, which is the main component of the mineral. It has a GRapi (Gamma Ray American Petroleum Institute Units) of 4,352,567.33. It has a concentration of 229.75 measured in GRapi. Other chemical elements included in vandenbrandeite are oxygen (23.9%), copper (15.82%) and hydrogen (1%). Although it is radioactive, the mineral is not fluorescent. It is a secondary mineral. ^[4]