Abundant small brown crystals of thermaerogenite on white aphthitalite and iron-black hematite and tenorite. Field width: 3.5 mm. — Photo: Pekov, I.V.; Sandalov, F.D.; Koshlyakova, N.N.; Vigasina, M.F.; Polekhovsky, Y.S.; Britvin, S.N.; Sidorov, E.G.; Turchkova, A.G. · CC BY 4.0
Thermaerogenite
Thermaerogenite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula CuAl₂O₄.
It crystallizes in the cubic crystal system (space group Fd-3m). It is a member of the Spinel structural group.
Key properties: Mohs hardness 7; specific gravity 4.87; Yellow streak; Vitreous luster.
IMA symbol Tag, IMA status: approved, named in 2018.
Found in cavities and overgrown on earlier oxide minerals, often epitaxially, as sublimates around a volcanic fumarole.
It is found associated with Tenorite, hematite, orthoclase (As-bearing), fluorophlogopite, langbeinite, anhydrite, calciolangbeinite, aphthitalite-type sulfates, krasheninnikovite.
A combination of the Greek θeρμόζ for “hot”, αέριον for “gas” and γενήζ for “born by”, which together “born by hot gas”, alludes to the fumarolic origin of the mineral.