Yellow smolyaninovite pseudom. after Erythrite, pale pink spheres Mansfieldite, red unaltered needles Erythrite and black Heterogenite; From: Mount Cobalt Mine, Selwyn District, Cloncurry Shire, Queensland, Australia. Photo and collection Fernando Brederodes. — Photo: Fernando Brederodes · CC0
Smolyaninovite
Smolyaninovite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Co₃Fe³⁺₂(AsO₄)₄·11H₂O.
It crystallizes in the orthorhombic crystal system. It is a member of the Smolyaninovite structural group.
Key properties: Mohs hardness 2; specific gravity 2.05–2.15; Silky luster.
IMA symbol Sya, grandfathered status — known before the IMA’s founding, named in 1956.
An oxidation product of Ni–Co arsenides.
It is found associated with Erythrite, pharmacolite, quartz.
The mineral was named to honor Professor Nikolai Alekseevich Smol’yaninov (1885–1957), Russian mineralogist, Moscow University, Moscow, Russia.