Yurmarinite
Yurmarinite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Na₇(Fe³⁺,Mg,Cu)₄(AsO₄)₆.
It crystallizes in the hexagonal crystal system (space group R-3c). It is a member of the Yurmarinite structural group.
Key properties: Mohs hardness 4.5; specific gravity 4.001; White streak; Vitreous luster; optically uniaxial.
IMA symbol Ymr, IMA status: approved, named in 2013.
Formed as sublimates on basaltic scoria around an active volcanic fumarole.
It is found associated with Hatertite, bradaczekite, johillerite, hematite, tenorite, tilasite, aphthitalite.
The mineral was named to honor Russian mineralogist, and specialist in the study of ore deposits, Yuriy Borisovich Marin (b. 1939), Professor of Mineralogy and Petrology.