Plavnoite

Plavnoite is a rare complex uranium sulfate mineral with the formula K0.8Mn0.6[(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. The Jáchymov site is known as a type locality for many rare and unique minerals.

Relation to other minerals
Although related to zippeite, plavnoite is chemically unique.