Becquerelite

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Becquerelite
Becquerelite-Uranophane-Uraninite-201144.jpg
Spray of becquerelite crystals with uranophane needles from the old Shinkolobwe mine
General
CategoryOxide mineral
Formula
(repeating unit)
Ca(UO2)6O4(OH)6·8(H2O)
Strunz classification4.GB.10
Crystal systemOrthorhombic
Crystal classPyramidal (mm2)
H-M symbol: (mm2)
Space groupPn21a
Unit cella = 13.8378 Å,
b = 12.3781 Å,
c = 14.9238 Å; Z = 4
Identification
ColourAmber-yellow, golden to lemon-yellow, yellow-orange, brownish yellow
Crystal habitTabular prismatic striated crystals exhibiting pseudohexagonal outline; coatings and fine-grained aggregates
CleavagePerfect on {001}; imperfect on {101}, {010} and {110}
TenacityBrittle
Mohs scale hardness2.5
LustreAdamantine to greasy
StreakYellow
DiaphaneityTransparent
Specific gravity5.09 - 5.2
Optical propertiesBiaxial (-)
Refractive indexnα = 1.725 - 1.735 nβ = 1.815 - 1.825 nγ = 1.825 - 1.830
Birefringenceδ = 0.100
PleochroismX = colourless to pale yellow, Y = Z = yellow to deep yellow
2V angleMeasured: 32°
Common impuritiesCommonly contains lead
Other characteristicsRadioactive
References[1][2][3]

Becquerelite is a uranium mineral with the chemical formula: Ca(UO2)6O4(OH)6·8(H2O). It is a secondary mineral which contains calcium and is a bright yellow colour. It has a Mohs hardness of about 2.

It was named after the French physicist Antoine Henri Becquerel (1852–1908), who discovered radioactivity in 1896. Becquerelite contains about 70% uranium by weight.

It is mainly mined in Kasolo of the former Zaire, in the present day Democratic Republic of the Congo.

References[edit]