Mcbirneyite is a very rare copper-vanadate mineral, forms tiny black crystals as inclusions or epitaxially grown with green stacked grown lammerite. The associating minerals are tiny black-red lyonsite needles, emerald green piypite needles and rich black microcrystalline coatings of hematite and orange microcrystalline coating of antimony bearing rutile. Very interesting and super rare combination. From: Yadovitaya Fumarole, Great Fissure, Tolbachik, Far Eastern Region, Russian Federation. — Photo: David Hospital · CC BY-SA 4.0
Lyonsite
A rare black copper-iron vanadate forming small well-formed orthorhombic tablets — first found on volcanic fumaroles.
Intro adapted from Wikipedia (CC BY-SA).
Lyonsite is an IMA-recognized mineral species in the vanadate class, with the chemical formula Cu²⁺₃Fe³⁺₄(VO₄)₆.
It crystallizes in the orthorhombic crystal system (space group Pmcn). It is a member of the Lyonsite structural group.
Key properties: specific gravity 4.215; Dark gray streak; Metallic luster.
IMA symbol Lyo, IMA status: approved, named in 1986.
Found in summit crater fumaroles, as a sublimate formed at ≤800 ° C.
It is found associated with Thenardite, howardevansite.
The mineral was named to honor Dr. John Bartholomew Lyons (1916–), Professor of Mineralogy, Dartmouth College, Hanover, New Hampshire, USA.