Fluorcarletonite-containing charoitite. The specimen is deposited at the Sidorov State Mineralogical Museum (Irkutsk, Russia). 1 – aegirine, 2 – pectolite, 3 – charoite, 4 – apophyllite-(KF), 5 – fluorcarletonite. The image is published in an article (Kaneva, E., Radomskaya, T., Suvorova, L., Sterkhova, I., and Mitichkin, M.: Crystal chemistry of fluorcarletonite, a new mineral from the Murun alkaline complex (Russia), Eur. J. Mineral., 32, 137–146, https://doi.org/10.5194/ejm-32-137-2020 , 2020.) distributed with an open acces license. — Photo: Kaneva, E., Radomskaya, T., Suvorova, L., Sterkhova, I., and Mitichkin, M. · CC BY 4.0
Fluorcarletonite
Fluorcarletonite is an IMA-recognized mineral species in the silicate class, with the chemical formula KNa₄Ca₄Si₈O₁₈(CO₃)₄F·H₂O.
It is a member of the Carletonite structural group.
Key properties: Mohs hardness 4.5–5; specific gravity 2.491; optically uniaxial.
IMA symbol Fcto, IMA status: approved, named in 2019.
Found in an ultra-agpaitic, potassic alkaline complex.
It is found associated with Fluorapophyllite-(K), pectolite, charoite, apatite, aegirine.
The prefix indicates the F-dominant analogue of carletonite.