Masuyite

Masuyite is a uranium/lead oxide mineral with formula Pb[(UO₂)₃O₃(OH)₂]·3H₂O.[3]

Masuyite
Orange Masuyite coating crystals of cubic uraninite (to about 1 cm). Shinkolobwe mine, the type locality, Democratic Republic of the Congo.
General
Category	Oxide minerals
Formula (repeating unit)	Pb[(UO2)3O3(OH)2]·3H2O
IMA symbol	Msy[1]
Strunz classification	4.GB.35
Crystal system	Monoclinic
Crystal class	Domatic (m) (same H-M symbol)
Space group	Pn
Unit cell	a = 13.98 Å, b = 12.11 Å, c = 14.2 Å; Z = 2
Identification
Optical properties	Biaxial (-)
Refractive index	nα = 1.785 nβ = 1.895 nγ = 1.915
Birefringence	δ = 0.130
2V angle	Measured: 50° , calculated: 44°
Dispersion	extreme
Other characteristics	Radioactive
References	Masuyite on Mineralienatlas[2]

Masuyite was first described in 1947 for an occurrence in Katanga and named to honor Belgian geologist Gustave Masuy (1905–1945).[4]