Black microcrystals of the rare Cu vanadate mineral from the type locality in Izalco volcano, El Salvador. Very rich specimen! Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY 4.0
Ziesite
A copper vanadate discovered in 1980 as fumarole sublimates on El Salvador's Izalco volcano.
Intro adapted from Wikipedia (CC BY-SA).
Ziesite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Cu₂V⁵⁺₂O₇.
It crystallizes in the triclinic crystal system (space group C2/c).
Key properties: specific gravity 3.86; Reddish brown streak; Metallic luster; refractive index 2.055; optically biaxial.
IMA symbol Zie, IMA status: approved, named in 1979.
Found in vanadium-bearing sublimates in fumaroles on a basaltic volcanic cone.
It is found associated with Stoiberite, shcherbinaite, bannermanite, fingerite, mcbirneyite, blossite, chalcocyanite, chalcanthite.
The mineral was named to honor Dr. Emanuel G. Zies, Carnegie Institute, Washington, D.C., USA.