BSE images of hellandite-(Ce) (Hel-(Ce)) and ferri-mottanaite-(Ce) (Fe-mot-(Ce)). (a) Crystal n.1 of hellandite-(Ce); (b) Crystal n.1 of hellandite-(Ce) with pyrochlore (Pcl) group members inclusion; (c) Cribrose core of crystal n.2 of hellandite-(Ce); (d) Hellandite-(Ce)-ferri-mottanaite-(Ce) exsolution in crystal n.2. The light bands represent hellandite-(Ce), the darker ferri-mottanaite-(Ce); (e) Ferri-mottanaite-(Ce) in close association with baddeleyite (Bdy) in crystal 2; (f) Brockite (Brck) disseminated in hellandite-(Ce)-ferri-mottanaite-(Ce) exsolution; (g) Crystal n.3 of ferri-mottanaite-(Ce); (h) Crystal n. 4 showing the cribrose core of hellandite-(Ce) and rim of ferri-mottanaite-(Ce). This image is published in an article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( https://creativecommons.org/licenses/by/4.0/ ). — Photo: Perna, Maria Grazia and Zaccaria, Daria and Rosatelli, Gianluigi and Stoppani, Francesco Saverio and Curti, Ezio and Spratt, John and Humphreys-Williams, Emma and Najorka, Jens and Brownscombe, Will and Nestola, Fabrizio and Stoppa, Francesco · CC BY 4.0
Ferri-mottanaite-(Ce)
Ferri-mottanaite-(Ce) is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₄Ce₂Fe³⁺(Be₁.₅ ₀.₅)[Si₄B₄O₂₂]O₂.
It crystallizes in the monoclinic crystal system (space group P2/a). It is a member of the Hellandite structural group.
Key properties: specific gravity 3.952; Very pale-yellow streak; Vitreous luster; optically biaxial.
IMA symbol Fmot-Ce, IMA status: approved, named in 2018.
Found in miarolitic cavities in feldspathoid-bearing alkali-syenitic pyroclastic ejecta.
It is found associated with Fluorite, sanidine, cancrinite, danburite, vonsenite, thorite/ekanite, magnetite, zircon, zirconolite, titanite.
The mineral was named to honor Annibale Mottana, Professor of Mineralogy, University of Roma Tre, Italy, for his leadership and support of investigations and cataloguing of the Latium minerals.