Umohoite

Umohoite is a rare oxide and hydroxide mineral. The name of this mineral reflects its composition: uranyl (U), molybdate (Mo) and water (H₂O). Its chemical formula is (UO₂)MoO₄·2H₂O.^[3]

Umohoite
General
Category	Oxide and Hydroxide
Formula	(UO2)MoO4·2H2O
IMA symbol	Umo[1]
Crystal system	Triclinic
Identification
Color	Black, blue-black, dark green, orange-red [2]
Cleavage	Perfect on {001}
Mohs scale hardness	2
Luster	Vitreous
Streak	Blue gray
Diaphaneity	Opaque
Density	4.53 - 4.66 g/cm3 (Measured) 4.49(3) g/cm3 (Calculated)
Refractive index	nα = 1.660 nβ = 1.831 nγ = 1.915
2V angle	Measured: 65°, Calculated: 64°
Other characteristics	Radioactive

Umohoite's type location is in Marysvale, the mineral was first described by Paul F. Kerr and G. P. Brophy in 1953.^[4]