Plavnoite

Plavnoite is a rare complex uranium sulfate mineral with the formula K_0.8Mn_0.6[(UO₂)₂O₂(SO₄)]•3.5H₂O. Typically for the secondary uranium mineral, plavnoite contains uranyl groups. It was discovered in the Plavno mine in Jáchymov, Czech Republic.^[2][3] The Jáchymov site is known as a type locality for many rare and unique minerals.^[4]

Plavnoite
General
Category	Sulfate
Formula	K0.8Mn0.6[(UO2)2O2(SO4)]•3.5H2O
IMA symbol	Pvn[1]
Crystal system	Monoclinic
Crystal class	Prismatic (2/m) (same H-M symbol)
Space group	C2/m
Unit cell	a = 8.63, b = 14.28, c = 8.86 [Å], β = 104.04° (approximated)
Identification
Other characteristics	Radioactive
References	[2]

Relation to other minerals

Although related to zippeite,^[2] plavnoite is chemically unique.^[5]