Black crystals of the rare lanthanum and cerium mineral perrierite-(La) asssociated to loparite and pyrochlore from Buer, Bjørkedalen, Porsgrunn, Telemark, Norway. Ex.F.Bauer collection. — Photo: David Hospital · CC BY-SA 4.0
Perrierite-(La)
Perrierite-(La) is an IMA-recognized mineral species in the silicate class, with the chemical formula (La,Ce,Ca)₄(Fe²⁺,Mn)(Ti,Fe³⁺,Al)₄[(Si₂O₇)O₄]₂.
It crystallizes in the monoclinic crystal system (space group P2_1/a). It is a member of the Chevkinite structural group.
Key properties: Mohs hardness 6; specific gravity 4.791; Brown streak; Vitreous luster; optically biaxial.
IMA symbol Prr-La, IMA status: approved, named in 2010.
Found in miarolitic cavities in sanidinite lava rock, probably pneumatolytic.
It is found associated with Sanidine, phlogopite, pyrophanite, zirconoiite, jakobsite, magnetite, fluorcalciopyrochlore, zircon.
The name refers to the La-dominant member of the perrierite structure type.