Oxiphlogopite with calcite - Germany, Rhineland-Palatinate, Eifel, Bell, Am Rothenberg Quarry (TL) - 2 mm Photos from tomeikminerals.com can be used under a Creative Commons Licenese 4.0 CC-BY, as explained in: https://www.tomeikminerals.com/about-me . — Photo: Henk Smeets - Tomeik Minerals · CC BY 4.0
Oxyphlogopite
Oxyphlogopite is an IMA-recognized mineral species in the silicate class, with the chemical formula K(Mg,Ti,Fe)₃[(Si,Al)₄O₁₀](O,F)₂.
It crystallizes in the monoclinic crystal system (space group C2/m). It is a member of the Mica structural group.
Key properties: Mohs hardness 3; specific gravity 3.06; Brown streak; Vitreous luster; optically biaxial.
IMA symbol Ophl, IMA status: approved, named in 2009.
Pneumatolytic crystals coat vugs in alkaline basalt.
It is found associated with Nepheline, plagioclase, sanidine, augite, diopside, magnetite.
The name refers to its composition (oxy) and relationship to phlogopite.