Dark green almost black microcrystals of the very rare Cu vanadate mineral stoiberite from the TL in El Salvador (Izalco Volcano, Sonsonate Department, El Salvador) and one of only two known localities worldwide. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY 4.0
Stoiberite
Stoiberite is an IMA-recognized mineral species in the vanadate class, with the chemical formula Cu₅O₂(VO₄)₂.
It crystallizes in the monoclinic crystal system (space group P2_1/c).
Key properties: specific gravity 5; Reddish brown streak; Metallic luster; optically biaxial.
IMA symbol Sbe, IMA status: approved, named in 1979.
A very rare mineral, deposited in vanadium-bearing sublimates in fumaroles on a basaltic volcanic cone.
It is found associated with Shcherbinaite, ziesite, fingerite, bannermanite, chalcocyanite, chalcanthite.
The mineral was named to honor Dr. Richard Edwin Stoiber (1911–2001), Emeritus Professor of Geology, Dartmouth College, Hanover, New Hampshire, USA.