Chemistry:Becquerelite

Becquerelite
Spray of becquerelite crystals with uranophane needles from the old Shinkolobwe mine
General
Category	Oxide mineral
Formula (repeating unit)	Ca(UO2)6O4(OH)6·8(H2O)
Strunz classification	4.GB.10
Crystal system	Orthorhombic
Crystal class	Pyramidal (mm2) H-M symbol: (mm2)
Space group	Pn21a
Unit cell	a = 13.8378 Å, b = 12.3781 Å, c = 14.9238 Å; Z = 4
Identification
Colour	Amber-yellow, golden to lemon-yellow, yellow-orange, brownish yellow
Crystal habit	Tabular prismatic striated crystals exhibiting pseudohexagonal outline; coatings and fine-grained aggregates
Cleavage	Perfect on {001}; imperfect on {101}, {010} and {110}
Tenacity	Brittle
Mohs scale hardness	2.5
Adamantine to greasy|re|er}}	Adamantine to greasy
Streak	Yellow
Diaphaneity	Transparent
Specific gravity	5.09–5.2
Optical properties	Biaxial (−)
Refractive index	nα = 1.725 – 1.735 nβ = 1.815 – 1.825 nγ = 1.825 – 1.830
Birefringence	δ = 0.100
Pleochroism	X = colourless to pale yellow, Y = Z = yellow to deep yellow
2V angle	Measured: 32°
Common impurities	Commonly contains lead
Other characteristics	Radioactive
References

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.