Very nice and well formed rakovanite crystals from the type locality: Sunday Mine, Slick Rock Mining District, San Miguel Co., Colorado, USA. — Photo: David Hospital · CC BY-SA 4.0
Rakovanite
A transparent brittle ammonium-sodium decavanadate of the pascoite family.
Intro adapted from Wikipedia (CC BY-SA).
Rakovanite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula (NH₄)₃Na₃[V₁₀O₂₈]·12H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/n). It is a member of the Pascoite structural group.
Key properties: Mohs hardness 1; specific gravity 2.407; Orange-yellow streak; Subadamantine luster; optically biaxial.
IMA symbol Rkv, IMA status: approved, named in 2010.
A secondary mineral as crystalline crusts on sandstone fractures in mine walls in the oxidized zone of a montroseite-corvusite assemblage.
It is found associated with Calcite, montroseite, corvusite, hughesite, hewettite, pascoite, munirite, paramontrosite, rosasite, sherwoodite.
The mineral was named to honor Dr. John Rakovan (b. 1964), professor, Department of Geology and Environmental Earth Science, Miami University, Oxford, Ohio, USA.