Coulsonite
Coulsonite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Fe²⁺V³⁺₂O₄.
It crystallizes in the cubic crystal system (space group Fd3m). It is a member of the Spinel structural group.
Key properties: Mohs hardness 4.5–5; specific gravity 5.17–5.2; Dark brown to black streak; Metallic luster.
IMA symbol Cou, IMA status: approved, named in 1937.
Found in veinlets of magnetite, with silicate minerals, cutting metamorphosed andesite (Buena Vista Hills, Nevada, USA); exsolved from magnetite in a mantle xenolith in basalt (Panzhihua, China).
It is found associated with Magnetite, scapolite, apatite, titanite, chlorite, “hornblende”, muscovite (Buena Vista Hills, Nevada, USA).
The name refers to Dr. Arthur Lennox Coulson (1898–?), geologist of the Indian Geological Survey.