:Locality: Taghouni Mine, Bou Azzer, Drâa-Tafilalet Region, Morocco Size: 5.5 × 4.1 × 3.5 cm Description: Metanováčekite from this Moroccan mine is very rare and appeared only in a reduced area. Tabular yellowish crystals, translucent and accompanied by metazeunerite. These crystals were transparent when collected, as nováčekite, but in few weeks all specimens are losing water and become translucent to opaque. — Photo: Joan Rosell , from rosellminerals.com · CC BY-SA 4.0
Metanováčekite
Metanováčekite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Mg(UO₂)₂(AsO₄)₂·8H₂O.
It crystallizes in the tetragonal crystal system (space group P4/n).
Key properties: Mohs hardness 2–2.5; specific gravity 3.51; optically uniaxial.
IMA symbol Mnvč, IMA status: approved, named in 1964.
Typically a dehydration product of nováčekite.
It is found associated with Nováčekite (Germany, England); bassetite, saléeite (Sue mine, Arizona, USA).
The prefix meta- denotes the dehydration product of nováčekite.