Figure 1. Ferriakasakaite-(Ce), as prismatic crystals in calcite, up to 1 mm long. Collection Museo di Storia Naturale, University of Pisa (catalogue number 19903). — Photo: Biagioni, C.; Bonazzi, P.; Pasero, M.; Zaccarini, F.; Balestra, C.; Bracco, R.; Ciriotti, M.E. · CC BY 4.0
Ferriakasakaite-(Ce)
Ferriakasakaite-(Ce) is an IMA-recognized mineral species in the silicate class, with the chemical formula CaCeFe³⁺AlMn²⁺(Si₂O₇)(SiO₄)O(OH).
It crystallizes in the monoclinic crystal system (space group P2_1/m). It is a member of the Epidote structural group.
Key properties: Mohs hardness 5.5–6; specific gravity 4.02; Brown streak; Vitreous luster.
IMA symbol Fak-Ce, IMA status: approved, named in 2018.
Found in a manganese deposit in metasedimentary rocks.
It is found associated with Calcite, hematite, manganiandrosite-(Ce), “androsite-(Ce)”, epidote.
A prefix identifies the dominant cation at the M(1) site (other than Al).