Obradovicite-NaNa
Obradovicite-NaNa is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula [Na₂(H₂O)₁₆Na(H₂O)₆][Mo₈As₂Fe³⁺₃O₃₃(OH)₄].
It crystallizes in the orthorhombic crystal system (space group Pnmb). It is a member of the Betpakdalite structural group.
Key properties: Mohs hardness 2; specific gravity 2.635; Very pale yellowish green streak; Vitreous to subadamantine luster; optically biaxial.
IMA symbol Obr-NaNa, IMA status: approved, named in 2011.
A rare secondary mineral found in the oxidized zone of a Cu-Mo porphyry deposit.
It is found associated with Quartz, muscovite, rutile, jarosite, gypsum, blödite, atacamite.
The mineral was named to honor Martin T. Obradovic, who provided the studied material. Two suffixes correspond to the dominant cations in the two different types of non-framework cation sites.